OP 23 

Spear: The Toot

to-Tail Ratio (T3R

in Modern Milita

Operations
 

John J. McGrath
 

The Long War Series
 

Occasional Paper 23
 

Combat Studies Institute Press 

Fort Leavenworth, Kansas 

OP 23

The Other End of 

Spear: The Too

to-Tail Ratio (T3

in Modern Milita

Operations
 

John J. McGrath 

Combat Studies Institute Press 

Fort Leavenworth, Kansas 
 

McGrath, John J., 1956-

The Other end of the spear : the tooth-to-tail ratio (T3R) in modern mil

operations / John J. McGrath.

 p. cm.

 Includes bibliographical references and index.
 

1. Deployment (Strategy)--Case studies. 

I. Title. 

U163.M393 2007

 355.4--dc22

 200

CSI Press publications cover a variety of military 

topics. The views expressed in this CSI Press pub

are those of the author(s) and not necessarily thos

Department of the Army or the Department of Def

full list of CSI Press publications, many of them a

for downloading, can be found at http://usacac.ar

CAC/csi/RandP/CSIpubs.asp. 

The seal of the Combat Studies Institute authentica

document as an official publication of the CSI. It is prohibited to use 

official seal on any republication of this material without the expressed 

permission of the Director of CSI. 

This is the Official US Government ed

this publication and is herein identified to 

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ISBN prefix is for US Government Printing 

Official Editions only. The Superintend

Documents of the US Government Printing 

requests that any reprinted edition clearly be labeled as a copy of the au

work with a new ISBN. 
John McGrath’s The Other End of the Spear is a timely h

analysis and an important follow-on work to his earlier analysis 

density trends in CSI Occasional Paper 16, Boots on the Ground. 

work showed, this paper also shows the timeless value of hist

its relevance to current events. Boots on the Ground analyzed t

between the numbers of troops employed in military operations 

to the population in a number of irregular confl icts. This study a

the composition of such forces to answer the question: what ha

the historical trends in the ratio of deployed forces directly eng

fighting, relative to those engaged in noncombat functions? This 

commonly, if inaccurately, called the “tooth-to-tail ratio.” 

McGrath’s study finds that the tooth-to-tail ratio, among t

deployed US forces, has steadily declined since World War II, ju

nature of warfare itself has changed. At the same time, the perce

deployed forces devoted to logistics functions and to base and life 

functions have both increased, especially with the advent of the lar

of use of civilian contractors. 

A segment of American military historians and policy makers h

been enamored with a genre of military history that seeks to quant

to reduce it to known variables, and to posit solutions to future 

conflicts based on mathematical formulae. The practice of war c

a strong element of science, but in the end, the practice of war i

This study cannot be used to guarantee victory simply by comp

force of the proportional figures presented in the conclusion. H

it does provide a good baseline, based on historical precedent, fo

planning. 

This work, coupled with Boots on the Ground, provides a 

analysis of the size and composition of military forces as found in h

patterns. Policy makers, commanders, and staff officers should u

two studies as a basis from which to begin their analysis of the pa

campaign at hand. They will then need to apply their understandin

objectives, the nature of the conflict, and local and regional cult

conditions to the analysis to create a winning military plan. It is ou

at CSI that this kind of historical analysis will inform and educate 

military and civilian leaders as they carry out our nation’s most im

policies. CSI—The Past is Prologue! 

Timothy R. Reese 

Colonel, Armor 

Director, Combat Studies Inst

This work marks my second foray into the field of quantitativ

sis of military history. As such, it serves as a companion volum

previous such work, Boots on the Ground: Troop Density in Cont

Operations. The latter work studied the question of “how many tr

we need?” This volume analyzes the question “what kind of troop

need?” While the tooth-to-tail ratio is a topic often discussed in 

circles, found far less frequently are detailed analyses of the propor

various elements within military force. I hope that this work fills th

Despite the quantitative nature of this work, the mathematics used 

elementary level, familiar even to most historians like myself. 

I must acknowledge the pioneer of quantitative analysis of 

history, the late Colonel Trevor Dupuy, as well as recent contrib

this field including Dr. Robert Rush of the US Army Center of 

History and Niklas Zetterling of the Swedish National Defense Co

Kendall Gott of the Combat Studies Institute’s Resear

Publications Team provided excellent support and guidance on this 

as did colleagues, superiors and associates within CSI. Contributing 

to the success of this project has been its editor, Jennifer Lindsey

skill at the intricacies of composition and layout are evident in ev

and graphic of this work. Publication was also greatly assisted 

efforts of Betty Weigand, Robin Kern and Michael Brooks. 

The soldiers of the United States Army and the members of t

armed services require specific acknowledgment. It is my hope

some small way, this study will augment their superb efforts. 

John J. McGrath 

Combat Studies Institute 

Fort Leavenworth, Kansas 

Foreword .........................................................................................

Acknowledgments...........................................................................

List of Figures.................................................................................

List of Tables ...................................................................................

Keys to Symbols Used in this Work ...............................................

Chapter 1. Introduction ...................................................................

Methodology .................................................................

Functional Tooth-to-Tail Categories .............................

Combat Elements ..........................................................

Noncombat Elements ....................................................

Logistical Elements ..................................................

Life Support Elements..............................................

Headquarters and Administrative Elements .............

Chapter 2. Historical Experience ....................................................

World War I ...................................................................

Theater Level ...........................................................

The AEF Division ....................................................

World War II ..................................................................

Overall Planning Estimates .....................................

The European Theater of Operations (ETO) ...........

Divisions in the ETO ...............................................

Korean War ...................................................................

Vietnam War ..................................................................

The Cold War Era, 1974 ................................................

The Nunn Amendment ............................................

ROAD Armored Division ........................................

Division 86/Army of Excellence/DESERT STORM 19

The Modular Army and the New Millennium...............

Stryker Brigades......................................................

Modular Brigades....................................................

Iraq and the Tooth-to-Tail Ratio ....................................

Summary .......................................................................

Chapter 3. Analysis .........................................................................

Overview.......................................................................

Combat Elements ..........................................................

Noncombat Elements ....................................................
Trends in Logistics ........................................................

The Rise of Headquarters..............................................

Life Support Functions..................................................

The T3R within Operational Units ...........................

Summary .......................................................................

Chapter 4. Conclusions ...................................................................

General Conclusions.....................................................

Trends and Ranges ........................................................

Trends ......................................................................

Ranges .....................................................................

Troop Density and the Tooth-to-Tail Ratio ...................

Summary .......................................................................

Glossary .......................................................................................

Bibliography ...................................................................................

Appendix A. T3R Categories ..........................................................

Table A-1. Categories of the Tooth and the Tail ......................

Appendix B. Comparative Data Tables ...........................................

Table B-1. Operational Unit (Division/Brigade) Composition 

Table B-2. Theater Comparisons by Category .........................

Table B-3. Operational Slice Comparisons ..............................

Table B-4. Overall Combat Forces Proportion .........................

Table B-5. Historical Data ........................................................

About the Author .............................................................................

List of Figures 

1. Historical Troop Density Ratio ...................................................

2. AEF Field Organization ..............................................................

3. AEF Breakdown, November 1918..............................................

4. Revised AEF Breakdown, November 1918 ................................

5. AEF Division Organization .........................................................

6. The AEF Infantry Division, 1918 ...............................................

7. Projected Army Ground Expeditionary Force, Mid-1943 ..........

8. ETO Organization .......................................................................

9. European Theater of Operations by Category, April 1945 ..........

10. ETO Infantry Division Organization ........................................

11. Infantry Division, 1945 .............................................................

12. ETO Armored Division Organization .......................................

13. Armored Division, 1943-45 ......................................................

viii 
14. Korean War Theater Organization, 1953 ..................................

15. Korea, July 1953 .......................................................................

16. Korea, July 1953, including Japan Base ...................................

17. Korean War Infantry Division Organization .............................

18. Infantry Division, July 1953 .....................................................

19. Vietnam War Theater Organization 1968 ..................................

20. Vietnam War Infantry Division Organization ...........................

21. ROAD Light Infantry Division, Vietnam 1968 ........................

22. US Army, Vietnam, April 1968 .................................................

23. Germany 1974 and 1976 Organization .....................................

24. US Army in Germany, March 1974 ..........................................

25. The Nunn Amendment Tooth-to-Tail Ratio ..............................

26. Armored Division Organization, 1974 ......................................

27. ROAD Armored Division, 1974 ...............................................

28. Armored Division Organization, 1986 ......................................

29. AOE Armored Division, 1986 ...................................................

30. Kuwaiti Theater of Operations (KTO), March 1991 ................

31. Stryker Brigade Organization, 2004 .........................................

32. Stryker Brigade, 2004 ...............................................................

33. Notional Modular Division Organization, 2004 .......................

34. Notional Modular Heavy Division, 2004..................................

35. Combined Arms Modular Brigade, 2004 ..................................

36. Modular Combined Arms Brigade, 2004 ..................................

37. Iraq, January 2005.....................................................................

38. Army Forces in Iraq, January 2005...........................................

39. Army Forces in Iraq including Contractor Support, January 20

40. Army Forces in Iraq including Contractor Support, Consolidat

by Category, January 2005 ...................................................

41. Army Forces in Iraq by Category, including Contractor Suppo

and Forces in Kuwait, January 2005 ...................................

42. Operational T3R Trends, 1917-2005 ........................................

43. Functional T3R Overview, 1917-2005 ......................................

44. Combat Proportion of the Army, 1917-2005 ............................

45. Combat Trends, 1917-2005 .......................................................

46. Noncombat Trends, 1917-2005 .................................................

47. Logistical Trends, 1917-2005 ...................................................

48. Headquarters Trends, 1917-2005 ..............................................

49. Life Support Trends, 1917-2005 ...............................................

50. Operational Unit Functional T3R, 1918-2005 ..........................

51. Functional T3R Averages, 1945-2007 ......................................
52. Combat Trends Since 1941 .......................................................

53. Functional T3R Trendlines .......................................................

54. Maximum and Minimum Functional T3R Levels ....................

55. T3R and Troop Density .............................................................

List of Tables 

1. AEF Operational Slice ................................................................

2. WW II US Army Operational Slice ............................................

3. Korean War US Army Operational Slice ....................................

4. Vietnam War US Army Operational Slice ..................................

5. Cold War 1974 US Army Operational Slice ...............................

6. DESERT STORM US Army Operational Slice ..........................

7. Modular Army Projected Brigade Operational Slice, 2007 ........

8. Iraq, January 2005, US Army Operational Slice .........................

9. Range of Functional T3R Percentages by Category ...................

10. Range of Functional T3R Percentages Based on Minimum 

and Maximum Combat Percentages.........................................

x 


Introduction 

This work is a companion to a previous volume entitled Boot

Ground: Troop Density in Contingency Operations. Boots on the 

analyzed historical precedent to develop a planning factor or aver

ure for the number of troops employed in successful contingency 

tions. The emphasis in that work was on the total number of troops 

not the specific type of troops within that total. The historical ex

represented various counterinsurgency, occupation and peacekeep

erations since 1900. It also looked at the organization and size of 

porary police forces, whose operations generally resemble count

gency and peacekeeping activities. 

Boots on the Ground concluded that a force of 13.26 troops 

thousand of local population was the minimum size needed based 

torical precedent, with a minimum of 4.1 (roughly one-third of th

devoted to police (i.e., combat in a counterinsurgency environm

ties. The rest of the force (9.16) could also conduct police dutie

other types of tasks that the force needed (Figure 1). 

POLICE 

AND OTHER 

DUTIES 

9.16 

POLICE 

TYPE 

DUTIES 

4.1 

13.26 PER THOUSAND
 

Figure 1. Historical Troop Density Ratio. 
really address (aside from the minimum number of police troops) t

position of such a force, be it the historically based correct size. T

cally, the composition of such an adequately sized force could co

an inadequate proportion of elements to complete its assigned miss

complete the picture, the current work looks at the composition o

in historical campaigns or deployments, rather than their total num

analyzes the composition of forces from historical US Army exped

operations using a quantitative methodology similar to that found 

on the Ground. This book looks at several troop categories based 

mary function and analyzes the ratio between these categories to 

a general historical ratio.1 

This ratio is called the Tooth-to-Tail Ratio (T3R). By defi nit

T3R refers to the number of troops in a military organization emp

combat duties versus the number functioning in noncombat roles. T

historical analysis, this volume will develop trends concerning the 

modern military forces. The book presumes that historical trends 

insight into the typical or most desirable T3R and that conclusion

on historical trends can be drawn. 

Methodology 

In certain respects, the methodology in this work differs from 

Boots on the Ground. While Boots used historical averages of for

from contingency operations and police forces, this work analyzes 

expeditionary operations and deployments since World War I, rat

just contingency operations. The reason for this shift is the author

that in any operation requiring the employment of an armed for

combat elements), while its size may differ based on the mission t

internal T3R of such forces remains similar. 

Additionally, while this work will also develop historical aver

cause of the ranges of its factors, this volume also focuses on h

trends. In most cases, US forces were assembled for specifi c exped

operations or deployments. Force planners in the past designed 

between combat and noncombat elements generally based on prior 

ence or around the number of combat forces. 

The methodology in this work depends on documentary sour

marily those of force orders of battle, official histories and tables 

nization. Undoubtedly unnoticed in documentary sources is the c

practice found in modern armies called taking “out of hide.” Out o

the tasking of individuals and groups from combat units to perfo

2 
as combat troops. In such instances, the tooth-to-tail ratio may act

higher (i.e., the tail being larger) than is apparent from the types an

bers deployed. Where possible, anecdotal evidence has been exam

determine whether out of hide issues were present in a particular h

deployment. 

The following chapter examined the evolution and proportio

tribution of the combat and noncombat elements in US Army exp

ary operations. Specific case studies include World War I; the E

Theater of World War II; Vietnam; Cold War Germany 1974; the D

86 organizational change; DESERT STORM 1990; the modular A

ganizational structure; and the deployment to Iraq, using Janua

as the snapshot. Except in the case of purely organizational chan

examination of each historical example looked at two levels: the

division. In this work, the T3R was investigated for each level, u

ders of battle and troop lists as source documents. Specific instanc

historical record where the tooth-to-tail ratio became an issue, su

the 1944 European Theater infantry shortage, were analyzed as w

Each historical scenario was examined from two angles. The fi 

the operational approach (operational T3R) and the second was by 

ual unit or category (functional T3R). In the former, the T3R was lo

Army wide. Army force planners organize the force into basic ope

units to fight wars or conduct operations. For most of the period c

this unit was the division. Under the US Army’s modular concep

oped early in the 21st century, the brigade replaced the division in t

In either case, a comparison of the Army’s basic operational units a

proportion of the Army and theater forces provided a general app

what portion of the army is in its basic combat elements. This work 

at the operational unit proportion for each scenario presented. 

The operational unit approach, heretofore referred to as the 

tional T3R, is less exact than the second, unit or category appro

this approach, which will be referred to as functional T3R, Arm

of battalion and above were divided internally, while company-si

were classified as a whole, into specific categories based on their 

function. After a unit-by-unit compilation, the proportion of the ca

to each other was determined for each scenario to establish the sc

functional T3R. The next section of this chapter details the catego

Following this look at the historical case studies, the scena

examined as a whole for historical commonalities and trends. Fr

analysis were drawn general historical trends and conclusions. 
Usually T3R refers to the contrast between fighters (combat 

and support or logistical troops. However, in modern expeditiona

fare, the variety of troops who serve in units or elements whose di

mary mission is not to fight the enemy has grown to include such 

nel as those operating life support functions at bases, reporting ev

service publications, and those serving in headquarters elements a

removed from the likelihood of direct combat action. Therefore, 

of functional T3R, this work looks at four specific categories of 

combat, headquarters or administrative, logistical, and life suppor

categories are summarized in the table in appendix A. 

Combat Elements 

The category of combat pertains to elements whose primary 

is to fight the enemy. While this includes the traditional comb

of infantry, armor, cavalry, field and air defense artillery, it m

include many other elements organized or dragooned into a prim

of fighting the enemy. Combat support units, such as combat en

assault helicopter units, antitank units and reconnaissance elem

noncavalry combat units are also inherently defined as combat e

(in comparison to the noncombat elements discussed below). 

In 1974, the US Congress codified what it considered to 

combat component of the Army. This classification included batta

smaller units of infantry, armor, field artillery, air defense artillery, 

engineers, Special Forces and aviation.2

 However, since there are 

headquarters and logistical contingents even in combat battalio

work makes a finer distinction. For example, an infantry battali

four rifle companies has more combat power than one with only th

companies. But such a battalion has the same support and head

elements. Accordingly, battalion-level support and headquarters e

are also factored into the analysis. Additionally, there are some e

which may or may not be considered to be combat elements b

the overall situation and their employment. Such units are consid

part of the combat category only if their primary role was the con

combat operations. For example, in a counterinsurgency operatio

there is not a rear area, military police (MP) units operating as 

security are conducting combat operations. However, MP units gu

prison that houses US prisoners awaiting court-martial are not. 

Consequently, this work includes as combat components co

size and above, units of infantry, armor, cavalry, field artillery, air 

4 
in this category are special operations forces (SOF) units of a

(which possess only small headquarters and logistics elemen

advisors supporting the combat units of foreign armies, as well as 

police and other units providing convoy protection (not self-pro

an inherent function of all deployed Army units) in forward areas

unit headquarters and headquarters companies (HHC) primarily co

noncombat headquarters elements, combat elements found in suc

for example a scout platoon in an armored battalion HHC, for the 

this work, are categorized as combat elements. 

Noncombat Elements 

Noncombat elements are the “tail” in the tooth-to-tai

Traditionally, the tail has been considered to be the logistical e

such as supply trains and maintenance workshops supporting 

But in modern expeditionary armies, the noncombat component 

complicated. Supporting troops may be divided into those e

directly supporting a combat organization, here referred to by c

as logistical elements, and the support troops who run the base 

and provide other support (such as post newspapers, base infrast

theater infrastructure, base construction) that is separate from the 

of operational missions. In this work, troops and units involved 

activities are called life support elements. 

All Army units, whether combat, logistical or life support in f

have headquarters and administrative elements to direct their ope

In 1974, Congress recognized such units, usually found in the 

headquarters companies or detachments, to be noncombat elem

levels above battalion. Although defined down to a lower level tha

Congress, this is the third category of noncombat elements.3 

Logistical Elements 

The category of logistical elements consists of military unit

primary mission is to provide support to combat units and t

logistical units providing support to combat units. Falling in

category are most Army combat service support units: quarte

supply, service, maintenance, ordnance, ammunition support, 

general, transportation, medical, and small finance detachments. E

from this category are the headquarters elements of such units 

primary mission is to control such units. Also included in this cate

the internal logistical elements in both combat and logistical ba

Medical hospital units are specially organized to establish and run h
are an integral part of the functioning of the hospital and are con

as logistical elements rather than headquarters elements. In thi

aviation units with medical evacuation or heavy-lift missions 

considered to be part of the logistical category. Despite their pr

role in counterinsurgency operations, civil affairs units, becaus

way they are organized, equipped and deployed, are considered als

within this category. 

The type and quantity of equipment found in the combat e

being supported has a direct impact on the size of logistical for

example, units outfi tted with armored vehicles need larger contin

maintenance support and ammunition-carrying vehicles. This stud

at trends in the proportion of logistical forces based on the develop

large motorized and mechanized forces. 

Life Support Elements 

Life support elements are those that provide infrastructure 

that is generally separate from the support provided to combat un

category includes the establishment of semipermanent camps an

as well as morale, welfare and recreation (MWR) facilities. Life 

elements, designated as a separate noncombat category, is a pa

characteristic of the US Army. In their large expeditionary opera

Europe in World War II, in Vietnam in the 1960s and Iraq in the pres

US forces established huge infrastructure organizations in the re

theaters. Where troop deployments were executed as part of a ro

scheme, this infrastructure remained in place as the troops rota

were replaced.4 

In most cases, life support functions are not operationally e

to the completion of the missions of the combat units. Types 

falling into this category include: base command and support unit

infrastructure units, engineer units with primary missions of infras

construction and support, fi nance offices, judge advocate general 

labor service support units, base public information units, and con

units. Medical units running facilities such as base dispensaries

function separately from the operational medical support system, 

included in this category. 

Units and elements devoted primarily to life support functi

sometimes, particularly in earlier periods, difficult to discern from lo

elements in documentary records and troop lists. In the historica

in the following chapter where this occurs, the categories of logist

life support are merged into a single category called logistical. 

6 
Headquarters and administrative elements form a third com

somewhere in the middle between combat troops and support troop

there may be some debate over whether headquarters elements of 

units, particularly those at lower levels, are combat troops or non

troops, this work considers the headquarters elements of all unit

than the company echelon as a separate category of noncombat 

This category includes not just headquarters elements of comb

but also those of headquarters units themselves and of logistical 

support units. This element is composed of troops whose primary fu

are devoted to the command and control of other troops or the su

the command and control of other troops. 

This category also contains administrative troops who work 

of a unit headquarters or whose primary mission is to help the co

disseminate information, escort visitors or conduct ceremonies. Ex

of such administrative troops are command information units

and administrative companies, such as those found in modern U

separate brigades, whose missions are to augment the staff stre

their higher headquarters. 

The development of large headquarters units is a relatively 

development in the evolution of armies. Prior to World War I, A

military organizations traditionally had small headquarters. W

Continental Army rejected the British organizational concept th

grade officers in regiments were also company commanders, b

shorting three companies of their full complement of offi cers, A

regimental headquarters organization was still miniscule by later sta

In the 1776 infantry regiment, the headquarters consisted of 13 

and specialists out of a force of 733, less than 2 percent of the reg

strength. This proportion remained standard throughout the 18th a

centuries. 5 

Above the regimental level, higher units, such as brigades and di

were temporary wartime expedients which had tiny staffs usually 

by acts of Congress. In 1861, at the beginning of the Civil War, C

decreed that a divisional headquarters would have a staff of four 

and a brigade headquarters of six. When the corps echelon of co

was authorized in 1862, the headquarters element consisted o

officers. Any additional staffing was taken out of subordinate units 

the small personal staffs that each general officer was authorized.6 

In addition to operational headquarters, the US Army fie

administrative structure of territorial-based headquarters called 
(subordinate to military divisions and usually commanded by a b

general). During wartime, department commanders usuall

commanded the operational forces within their department and led 

the field. In peacetime, where there was no operational level of co

above the regiment, military division and departmental commande

responsible for the operational employment and activities of a

units stationed within the geographical limits of their commands. D

and departmental commanders were taken from the small corps of 

officers. If there was no available general officer, a senior colo

detailed from his regiment to fill the post. 

From World War I to the present, with the US Army invo

extensive expeditionary operations across the globe, its head

elements have evolved and grown. An evolution of commun

technology has paralleled this growth, leading ultimately to the 

digital age and modular (at the brigade level) organization of th

With enhanced communications, however, there has not been a con

decrease in the size of headquarters, but the complete opposi

development is discussed later in this work. 

This chapter established terms and methodology to be used in 

at the operational and functional T3R. The next chapter appl

methodology to a sampling of major US Army expeditionary op

and deployments since 1917. 

8 
1. Boots on the Ground looked at contingency operations. Assum

tooth-to-tail ratios are applicable to all expeditionary operations, the an

this work will not be restricted to just contingency operations. 

2. John B. Wilson, Maneuver and Firepower: The Evolution of D

and Separate Brigades, Army Lineage Series (Washington, DC: US Arm

of Military History, 1998), 366, 376 note 31. 

3. Ibid. 

4. As the Operation IRAQI FREEDOM deployment extended into 

and third troop rotation, many casual observers (without historical back

commented on the American building of permanent bases in Iraq. For e

see Erik Leaver, “Building Permanent US Bases in Iraq Sends Wrong 

Seattle Post-Intelligencer, 15 May 2005 [article on-line] available 

seattlepi.nwsource.com/opinion/224055_iraqbases.html; Internet; access

March 2007; Doug Giebel, “Permanent Bases, Leave Iraq? Hell No, W

Go!” Counterpunch, 6 January 2004 [article on-line] available at http

counterpunch.org/giebel01062004.html; Internet; accessed on 21 Mar

These observers failed to realize that since World War II, the Americ

established such elaborate infrastructure wherever US forces were deploy

extended period of time and that while the facilities often looked like a pe

US presence, this was not the intent. By 2007, most of the permanent US 

had been handed over to the Iraqis. 

5. Robert Wright, The Continental Army (Washington, DC: U

Center of Military History, 1983), 47. 

6. Revised United States Army Regulations of 1861 (Washingt

Government Printing Office, 1863), 506, 539; Robert M. Epstein, “The 

and Evolution of the Army Corps in the American Civil War,” The Jo

Military History 55 (January 1999), 34. 

AEF

DEPOT

SOS

SOS

additional

non-divisional

combat units

AEF

DEPOT

SOS

SOS

Historical Experience 

World War I 

Theater Level 

When the United States entered World War I, its Army had h

limited experience with expeditionary warfare and no experienc

type of warfare being fought in France. Accordingly, the types of 

units needed in France were created from scratch. American p

made force development estimates based on the general principle

in the Army’s field service regulations and from looking at the exa

the composition of the French and British forces (Figure 2). The ea

projection was that support elements would be 20 percent (or a rati

combat versus support) of the expeditionary force. But, as the orga

developed, this percentage estimate was increased in September 

33 percent (or a ratio of 2:1 combat versus support).1 

CATEGORY- PRIMARY MISSION 

HEADQUARTERS COMBAT LOGIST

XXXXX X X 

XXXX

XXX

x2

x7

x30

X X

X X

SKELETON

x7 + + X

from

Depot Division

Artillery Brigades

CORPS

ARTY

+ +

AEF 

XXXX 

XXX 

x2 

x7 

x30 

X XXX 

DEPOT 

X X

SKELETON

XX 

SKELETON

x7 + + 

SOS 

X 

from

Depot Division

Artillery Brigades

CORPS 

ARTY 

+ + 

SOS 

additional

non-divisional

combat units

SOS = Services of Supply 

Figure 2. AEF Field Organization. 

A look at the AEF as fielded in November 1918 (Figure 3

that the logistical structure ended up being close to the Septemb

estimate, with 32 percent of the force devoted to what was the

“line of communications” operations. The US troops who depl
is therefore difficult to separate life support activities from logistic

Accordingly, the two are joined in the analysis of the proportional 

the American Expeditionary Force (AEF).2 

Logistics & 

Life Support 

32% 

77% 

9% 

14% 

Com

HQ/

Log

3% 

HQ/ 

Admin 

Combat Units 

65% 

Figure 3. AEF Breakdown, November 1918.3 

Headquarters at all levels of the AEF were austere. For exam

an organization of 1,866,184, only 31,813, or 1.7 percent, wer

in headquarters units. Together with troops supporting head

operations, the headquarters category comprised only 3 percent of th

The AEF itself maintained a headquarters of 4,271, less than 1 pe

the total AEF. Divisions with a size of 28,105 in November 1918, o

a headquarters element of 304 (1.1 percent). Infantry brigade head

controlled an organization with a strength of 8,072 with only 25 pe

(less than 1 percent). Infantry regimental headquarters were staff

349 personnel for a command of 3,770 (9 percent), of which 20

percent) were staff personnel, while infantry battalion headquarte

staff of 3 to lead a unit of 1,027 (less than 1 percent).4 

At the theater level, the functional T3R was 1.8 to 1 in favor of 

elements. Combat units (i.e., divisions) were 65 percent of the AE

breakdown in November 1918. These units also had their own lo

and headquarters elements. Figure 4 shows the theater level adju

the noncombat elements found in the divisions. Combat eleme

12 
8% 

39% 

Combat

Logistics

HQ/Admin

Combat 

Logistics 

HQ/Admin 

53% 

Figure 4. Revised AEF Breakdown, November 1918.5 

made up more than half (53 percent) of the AEF’s force structu

a function`al T3R of 1.1 to 1. Logistical elements formed slightly 

third of the revised structure (39 percent), while headquarters e

formed less than 1 in 10 (8 percent) of the deployed soldiers.6 

The AEF Division 

The AEF division (Figure 5) had an even higher functional T

the AEF as a whole. As shown in Figure 6, 78 percent of division

were devoted to combat operations (a ratio of 3.5 to 1 in favor of 

troops). Divisional headquarters elements roughly matched the pro

found at the theater level (9 percent versus 8 percent), but lo

elements within the division were a lot more austere (14 percent) to 

elements at the theater level (39 percent).7 

Despite this high proportion of combat troops in the divisio

was soon a shortage of infantry troops, forcing the AEF command 

some deployed divisions into depot organizations to process repla

and to skeletonize others. Of the 42 divisions operational in France 

and 1918, only 30 actually fought in the front lines, with 6 being co

to depot divisions and an additional 5 broken up to provide repla

for the 30 fighting divisions. Even the logistical forces eventually 

from shortages. In November 1918, the AEF broke up a newly 
TRAINS

HEADQUARTERSCOMBAT LOGISTI

X X

X

x2

III

x4

I I

x12

I I

x3

X I I

x7

III

x3

I I

III

X

HEADQUARTERS COMBAT LOGISTI

X X 

X 

III 

x2 

x4 

I I 

x12 

I I 

x3 

X II 

x7 

III

x3 III x3 

I I 

III 

X 

TRAINS 

Figure 5. AEF Division Organization. 

Combat

Logistics

HQ/Adm

Combat 

Logistics 

HQ/Adm

78.4% 

7.2% 

14.4% 

Figure 6. The AEF Infantry Division, 1918.8 

14 
Supply logistical command.9 

Even though the AEF division was austere in terms of head

elements, it provides a good example of how command and 

headquarters can be interjected into force structure when it is un

operationally. When the AEF was organized, planners wanted t

a machine gun company within every infantry battalion. H

Congress, in the National Defense Act of 1916, had restricted the 

regiment to a specific size. If the Army had assigned three mach

companies to an infantry regiment, the regiment would then lose 

its rifle companies. To bypass this restriction, force developers 

machine gun companies at three echelons: regiment, brigade and d

The infantry regiment received the one machine gun company 

keep within the restrictions. The brigade had a three-company b

Accordingly, between the regiment and brigade, there were a

machine gun companies for five of the six infantry battalions 

brigade. To provide for this remaining battalion, the division had 

company machine gun battalion, which provided two of its com

to fill out the machine gun company requirements for the two b

in the division. In 1918, these two companies were assigned dir

the brigade machine gun battalion, raising it to four companies. A

the machine gun companies were almost always used in direct 

of infantry battalions, making the machine gun battalion head

unnecessary, the AEF still maintained the headquarters.10 

As mentioned in the introduction, one method to look at T3R 

first used in World War II, but which can be retroactively applied t

War I, is to determine what percentage of the Army formed the po

it organized specifically to execute combat operations. In this wo

is the operational T3R. The Army employed specific units, divi

brigades, as its basic fighting elements. These are called the ope

units. The proportion of the Army organized in such units prov

indicator of what percentage of Army forces are in the fighting ech

this work, this portion is called the operational slice. Its size is det

by dividing the total strength of the Army by the number of ope

units in the Army’s force structure. This number is then compare

operational unit’s authorized strength. The result is the proportio

Army contained in the operational units. While the nondivisional e

can include headquarters and logistical elements, as well as nondi

combat elements, they provide a useful guideline in determining t

the relative number of troops in the force in comparison to those 
formed 50 percent of the whole Army and 45 percent of the AEF. 

Table 1. AEF Operational Slice 

Total Army 

a. b. c. d. e. f. 

Army Total AEF Operational Operational Non- 

StrengthStrength Divisions11 Division Slice Percentage Divisional D

Size (a/b) (c/d) Slice P

(d - c) of 

2,395,742 43 28,105 55,715 50 27,610 

AEF 

a. b. c. d. e. f. 

AEF AEF AEF Operational Operational Non- 

StrengthStrength Divisions Division Slice Percentage Divisional D

Size (a/b) (c/d) Slice P

(d - c) o

1,866,164 30 28,105 62,205 45 34,100 

While the World War I US division is considered to be gigantic 

in terms of the functional tooth-to-tail ratio it was austere in non

elements. Deployment to a developed theater with excellent infras

already in place assisted the AEF in retaining an austerity of non

elements. The next time the United States deployed a com

expeditionary force, it was not so lucky. 

World War II 

World War II was the United States’ ultimate experien

expeditionary warfare. The war the Army fought was completely o

and US forces were the main component in all theaters except Chin

Burma and Russia. The largest theater in terms of troops deployed 

European Theater of Operations (ETO). Troops in the ETO fought 

across France and into the heart of Germany in 1944-45. This sect

the example of the ETO to explore the expeditionary aspects of 

in World War II. 

Overall Planning Estimates 

As in World War I, the basic operational element in the US A

World War II was the combat division. During the war, Army lea

16 
29% 33%

COMBAT

UNITS

(DIVISIONS)

NONDIVISIONAL

COMBAT TOTAL

COMBAT

65%

36%

to maintain a large industrial base in the civilian sector and large num

air force and logistical troops in the military sector. Accordingly, th

raised only 89 divisions to fight in the war. Of these 89 divisions

armored divisions and 67 infantry divisions) possessed extensive 

logistical assets of their own as the bulk of the Army was motorized

heavy casualties affected the combat elements of the divisions, a pe

crisis ensued in late 1944 that required the conversion of thous

supporting troops to combat jobs.12 

As part of the process of creating and fielding the 89 divisi

Army Ground Forces (AGF), under Lieutenant General Lesley J. M

was the War Department agency responsible for developing the 

force including the correct mix between combat elements and sup

units. As such, the AGF became the agency most responsible for 

the tooth-to-tail ratio for the World War II Army. In planning, th

a great tendency for the tail to expand. McNair often fought hi

recommendations on this point. In mid-1943, when the AGF was ac

the last of the 89 divisions, McNair felt the projected expeditiona

structure (Figure 7) was askew. Only 29 percent of the force des

to fight the enemy was found in divisions. While McNair did not 

70 

PERCENT
 

60 

50 

40 

30 

20 

10 

0 

29% 33% 

COMBAT 

UNITS 

(DIVISIONS) 

NONDIVISIONAL 

COMBAT TOTAL 

COMBAT 

65% 

36% 

Total
 

Combat
 

2%
 

Theater Service
 

Overhead Support
 

Figure 7. Projected Army Ground Expeditionary Force, Mid-1943.
in tables of organization and equipment, giving divisions minimal 

elements, he did recognize that the proportion of the organization 

divisions was a direct indicator of the amount of combat power repr

in the Army.14 

McNair’s concerns were well founded. The projected 65-perce

of combat elements (before subtracting organic headquarters and 

elements) was, in fact, never met when the Army’s ground forces 

deployed. By the end of the war, the ground forces operational s

risen to 67,900, with only 20 percent of ground troops found in d

(Table 2). 

Table 2. WW II US Army Operational Slice15 

a. b. c. d. e. f. 

Total Number of Standardized andardized Operational Division Non- 

StrengthStrength Divisions Division Slice Percentage Divisional Di

Size (a/b) of the Army Slice Pe

(c/d) (d - c) of t

6,042,277 89 13,800 67,900 20 54,100 

The European Theater of Operations (ETO) 

The place to where most of the divisions (72 percent), which t

raised, were deployed was in the European Theater of Operation

(Figure 8). Into this largest of all theaters, 64 divisions deplo

defeated Germany in an 11-month campaign. Theater-wide, the fu

T3R at the end of the campaign is depicted by category in Figure 9

the theater, the ratio between combat and noncombat elements w

1.6. 

Compared with the AEF in the same general theater, ETO 

contained 14 percent fewer combat elements. This was dou

percentage of headquarters elements (16 versus 8) and an incre

percent among logistical/life support elements. That there wer

logistical elements than in World War I can be expected consider

the ETO deployed by assault into a theater with minimal infrastru

place, while the AEF deployed into a mature theater secured by Al

why did the number of headquarters double proportionally? 

18 
COMZ

COMZ

TD 13

FA 82

AAA 48

ENG 91

ENG 

ENG RGTS 5

TC 

TD 50

FA 257

AAA 165

ENG 169

COMZ 

COMZ

I I I I I I 

X XXXX

+ + 

X X X X X X 

XXXX 

CATEGORYPRIMARY MISSION 

HEADQUARTERS COMBAT LOGISTICLOGISTICAL 

ENG 

ENG RGTS 5

TC 

TD 50 

FA 257 

AAA 165 

ENG 169 

XXXXXX X X SHAEF/

ETO 

13 

FA 82 

AAA 48 

ENG 91 

x45 

TD 

+ + 

COMZ 

X X 

x2 x15 I I 

x137 X X X X 

x4 

I I 

x5 x641

x15 

x234* SHAEF = Supreme Command Allied Expedition

COMZ = Communications Zone 

TD = Tank Destroyer 

TC = Transportationportation Corps 

* INCLUDES BRIGADE HEADQUARTERS 

Figure 8. ETO Organization. 

16% 

45% 39% Life Supp

HQ/Admi

Combat

Logistics

Life Supp

HQ/Admi

Combat 

Logistics

Figure 9. European Theater of Operations by Category, April 194
increase in higher headquarters organizations brought about by the 

of forces employed and by the inclusion of headquarters elemen

larger logistics element, the Army’s basic philosophy of organizat

have also had something to do with the growth. As mentioned 

AGF head McNair believed in economizing tables of organizat

equipment (TOEs). He also felt that divisions should be organiz

only the minimum elements necessary for most operations a

additional elements would be attached to divisions only as ne

While in practice, this system, called streamlining and pooling, 

resulted in the semipermanent assignment of many of the pooled e

to divisions. It also meant that the pooled elements required admin

headquarters to command and control them while in pooled 

Accordingly, in the ETO, there were 234 such headquarters con

pooled units. To facilitate pooling, on 24 December 1942, the Army 

a new organizational system where it reorganized so that regimen

replaced by separate battalions in all arms and services except the i

Whereas battalions under regiments had had small headquart

usually no organic logistical elements, the separate battalions, bec

their possible independent employment, had sizable contingents 

In the ETO, there were 725 such battalions. Together, pooled head

and separate battalion headquarters elements consisted of 145,359 

forming 42 percent of the headquarters element slice of the ETO p

At the theater level, logistical/life support elements were 45 pe

the total troops employed. The level of these elements seems to ha

devised based on a combination of the number of troops to be su

(usually addressed in terms of specific unit types [army, corps, d

to be supported) and guesswork. For example, predeployment g

called for ordnance (ammunition and maintenance) units to com

percent of the total number of troops in a theater of operations. In th

this goal was exceeded, with ordnance troops reaching 7.1 percen

total deployed troop force. Several postwar studies considered th

support levels were adequate based simply on the overall succes

campaign. Nevertheless, they recommended modest increases in 

of logistical elements (Figure 10). 

For instance, one study recommended a 12.5 percent increas

number of service troops assigned to an army group. Despite this

of the ETO generally warned that no definitive conclusions concer

T3R could be drawn from the ETO because of its unique nature.18 

20 
RECON

ORD

QM

MP

HEADQUARTERSCOMBAT LOGISTIC

X X

III

x3

I I

x9

I I

x4

I I I

DIVISION

ARTILLERY

I

I

I

●●●

I I

HEADQUARTERS COMBAT LOGISTIC

X X 

III

x3 III x3 

I I

x9 II x9 

I I

x4 II x4 

I I I 

DIVISION

ARTILLERY

DIVISION 

ARTILLERY 

I 

RECON 

I 

ORD 

I 

QM 

●●●

MP 

I I 

Figure 10. ETO Infantry Division Organization. 

Divisions in the ETO 

Deployed in the ETO were a total of 62 divisions: 45 infa

armored and 4 airborne. Under the streamlining concept, these d

were organized to maximize their combat power. The functional T

in the 1945 infantry division is shown in Figure 11. Compared 

AEF predecessor, the 1945 division was half the size with 14,037 

28,105. While the proportion of logistical elements remained th

14% 

68% 

Combat

Logistic

HQ/Adm

Combat 

Logistic

HQ/Adm

18% 

Figure 11. Infantry Division, 1945.19 
ORD

QM

MP

TRAINS

was 9 percent smaller, with the difference being found in an in

headquarters element. Although the World War II division had eli

an echelon of command (the brigade), its headquarters staffs had in

A general expansion in the size of headquarters elements can acc

part of this increase. The reorganization of the division’s artillery

separate battalions and a divisional artillery headquarters had repl

artillery regiment with organic battalions, also played a role. Des

expansion of command and control elements, the World War II 

division was still primarily a combat organization, with one an

combat soldiers for every support soldier (Figure 12). 

HEADQUARTERS

CATEGORY- PRIMARY MISSION

COMBAT LOGIS

x3

x3

I

DIVISION

ARTILLERY

I I

I I

●●●

X X I I I I

I I

x3

X COMBAT I I

COMMAND x3

I I

X I I

HEADQUARTERS 

CATEGORY- PRIMARY MISSION 

COMBAT LOGIS

x3 

x3 

I 

DIVISION

ARTILLERY

DIVISION 

ARTILLERY 

I I 

ORD 

I I 

QM 

●●●

MP 

X X I I I I

I I

x3

II 

x3 

XCOMBAT I I

COMMAND x3 

I I 

XI I

TRAINS 

Figure 12. ETO Armored Division Organization. 

The armored division was a new type of unit in the US Arm

fielded in World War II. The ETO divisions came in two organi

varieties: the older heavy division, which retained dual regimen

combat command headquarters and a large number of combat ba

and the new light division that was smaller. Of the 15 divisions in th

13 were of the light variety, so it is that organization which is di

here. Figure 13 shows the proportional organization for the a

division (light TOE). 

22 
21% 

58% 

Combat

Logistic

HQ/Adm

Combat 

Logistic

21% 

Figure 13. Armored Division 1943-45.20 

As would be expected in an organization with almost all of its 

elements mounted on tracked vehicles and almost all of its other e

mounted on wheeled vehicles, the logistical element in the a

division was larger than that in the infantry division. The armored 

support element was one-third larger than that of an infantry divi

percent to 14 percent). With the expanded mobility of the divisio

resulting in the organization being spread out across large areas a

its combat elements (tank and armored infantry) being organiz

separate battalions, support elements were more compartmentali

expanded than in the infantry division. 

Similar to events in 1918, once combat operations in th

commenced, a personnel crisis soon ensued. In both cases, the p

was that forward combat elements, particularly the infantry, took l

a higher rate than their proportion in the force, while there was n

pool of trained replacements. Almost from the start in July 194

infantry casualties were higher than projected. To keep up with 

such a pool needed to be larger than the combined strength of the 

in the operational units. In World War I, the AEF broke up uncom

divisions to provide replacements. InWorldWar II, however, the 89-

plan made this unfeasible as all the divisions were needed opera

and were supposed to be kept at full strength through a constant 

individual replacements.21 
of available infantry replacements. However, this left ina

replacements if the current rate of losses continued. Therefor

start, excessive replacements in combat branches were retra

infantry and the allocation of replacements in training was a

These measures did not resolve the problem, but it was partially ame

because infantry casualties fell from August through October 194

the July rate. But casualties rose again in November and the B

the Bulge in December turned the replacement shortfall into a cri

Army initiated programs to alleviate the shortage including the tra

participants of several specialist programs to infantry replacement 

and also transferring the reassignment of several divisions or

earmarked for the Pacific to Europe. But the ETO was forced to ta

immediate measures, primarily through finding new infantryme

theater assets. Most were being taken from logistical and head

elements, via calls for volunteers. In January 1944, the ETO head

centralized the effort to find new infantrymen from within theate

At the same time, Lieutenant General John Lee, the commande

Communications Zone (COMZ), the ETO’s theater logistical headq

gave each of his subordinate units quotas to produce infantry can

In mid-January, the ETO declared all enlisted men assigned to non

units, within certain conditions, to be eligible for transfer to the i

These measures from inside and outside the ETO, along with a 

operations from the high intensity battles as in the Ardennes, en

crisis. The ETO and War Department had underestimated the attrit

in the tooth and had to draw from apparently redundant assets in th

make up the difference.22 

Korean War 

Beginning only 5 years after the end of World War II, the Kor

was fought with many of the same organizational structures and eq

as the earlier conflict. Accordingly, the functional T3R in Korea 

resemble that of the ETO in World War II. The troops assemble

Korean peninsula reached their height in July 1953, at the tim

signing of the armistice ending the conflict (Figure 14). 

Figure 15 shows the functional tooth-to-tail ratio for the U

units deployed to South Korea at that time. In comparison to 19

combat portion of the force had gone up 3 percent, while head

elements had proliferated an additional 5 percent. To make up 

increase in combat elements, logistics/life support actually declin

World War II by 8 percent. The expansion of headquarters elem

24 
KCOMZ

KCOMZ

Cited battalions are battalion equivalents

AAA Antiaircraft Artillery MED Medical

AG Adjutant Genera MI Military Intelligence

AV Aviation MP Military Police

CHEM Chemical ORD Ordnance

ENG Engineer QM Quartermaster

FA Field Artillery SC Signal Corps

FEC Far East Command STA Station Complement 

KCOMZ Korea Communications Zone DET Detachment

TC Transportation Corps TK Tank

AAA 4 TC 2

FA 4 QM 3

MP 1 ORD 3

ENG 8 SC 6

CHEM 2 INF 1

TK 1 FA 23

AAA 10 ENG 11

FEC

Japan

Base

Japan

Base

MI 5 ENG 8

FA 1 TC 2

MP 1 QM 11

SC 1

STA

SC 

FIN 

ENG 

MED 

AG 

EIGHTH

KCOMZ FEC

Japan

Base

Japan

Base

STA

CATEGORYPRIMARY MISSION 

HEADQUARTERS COMBAT LOGISTICAL LIFE SUPPO

FEC 

XXXX 

EIGHTH 

+ + 

KCOMZ 

+ + 

Japan

Base 

X X X X X X 

I I I I I I 

I I 

XXXXX 

x3 CHEM 3 

Cited battalions are battalion equivalents 

AAA = Antiaircraft Artillery MED = Medical 

AG = Adjutant Genera MI = Military Intelligence 

AV = Aviation MP = Military Police 

CHEM = Chemical ORD = Ordnance 

x32* 

X X

x7 + +

III

x1

ENG 11

MP 15

AV 1

SC 4

QM 17

MED 20

HOSPITALS 12

I I

x48

I I

x83

+ +

DET

x4

x6

III

x1

I I

X X

x7

XX 

x7 + + 

KCOMZ 

III

x1

III 

x1 

ENG 11 

MP 15 

AV 1 

SC 4 

QM 17 

MED 20 

HOSPITALS 12 

I I

x48 II x48 

I I

x83 II x83 

CHEM 2 INF 1 

TK 1 FA 23 

AAA 10 ENG 11 

+ + 

Japan

Base 

DET

x4

DET 

x4

STA x6 

SC 

FIN 

ENG 

MED 

AG 

III

x1

III 

x1 

I I 

ENG = Engineer QM = Quartermaster x29 FA = Field Artillery SC = Signal Corps 

FEC = Far East Command STA = Station Complement 

KCOMZ = Korea Communications Zone DET = Detachment 

TC = Transportation Corps TK = Tank 

AAA 4 TC 2 

FA 4 QM 3 

MP 1 ORD 3 

ENG 8 SC 6 

MI 5 

FA 1 

MP 1 

SC 1 

ENG 

TC 

QM 

8 

2 

11 

* INCLUDES BRIGADE HEADQUARTERS 

Figure 14. Korean War Theater Organization, 1953. 

32% 42% 

21% 

Combat

Logistics

HQ/Admin

Life Suppo

Combat 

Logistics 

HQ/Admin 

Life Suppo

5% 

Figure 15. Korea, July 1953.23 
three corps and seven division headquarters, and a communicatio

headquarters controlling several major logistical headquarters e

But the decline of logistic elements appears curious considerin

since World War I and the expeditionary nature of the Korean op

The context of the war helps to explain the situation. While 

soldiers, including 89,361 logistical troops were in fact deployed 

Korea, the Army maintained a large logistical base in nearby Ja

many of the theater support elements were located there instead of i

itself. Figure 16 shows the functional T3R with the inclusion of the 

logistical troops (and their headquarters elements) in Japan. W

addition of the Japanese base, the Korean War functional T3R more 

resembles the World War II ETO figures in terms of logistics: 43 

to 45 percent in the ETO. Headquarters elements had still expand

percent from ETO totals, mostly at the expense of the combat e

which declined by 6 percent. While in the ETO there was one head

soldier for every seven total soldiers, in Korea, this ratio had cli

one headquarters staffer for every four soldiers. The ratio of co

noncombat soldiers was one to three in Korea in 1953. 

37% 

33% 

24% 

Combat

Logistics

HQ/Admin

Life Suppo

Combat 

Logistics 

HQ/Admin 

Life Suppo

6% 

Figure 16. Korea, July 1953, including Japan Base.24 

Since 1945, the Army had done away with some aspects of M

pooling concept. This resulted in additional divisional combat e

primarily in the form of increased field artillery cannons in each 

and the addition of an antiaircraft artillery (AAA) battalion and 

26 
RECON

ORD

QM

MP

REPL

larger than its 1945 equivalent, with a strength of 20,036 compare

14,037 of its predecessor organization.25 

Figure 17 depicts the categories in the 1953 infantry divisio

Figure 18 shows the functional T3R ratio. While the gross num

combat troops increased within the division, so too did logisti

HEADQUARTERS

CATEGORY- PRIMARY MISSION

COMBAT LOGISTICA

X X

III

x3

I I

x9

I I

x4

I I I

DIVISION

ARTILLERY

I

I I

I

I

I I

I

I I

I I

AW AW = Automatic Weap

REPL = Replacement

HEADQUART

III 

ERS 

CATEGORY- PRIMARY MISSION 

COMBAT LOGISTICA

X X 

x3 

I I

x9 II x9 

I I

x4 II x4 

I I I 

DIVISION

ARTILLERY

DIVISION 

ARTILLERY 

I 

RECON 

I I 

ORD 

I 

QM 

I 

MP 

I I 

I 

REPL 

I I 

I I

AW

II 

AW AW = Automatic Weap

REPL = Replacement 

Figure 17. Korean War Infantry Division Organization. 

18% 

20% 

Combat

Logistics

HQ/Adm

Combat 

Logistics 

HQ/Adm

62% 

Figure 18. Infantry Division, July 1953.26 
headquarters. And the additional combat elements were also equipp

vehicles and equipment, increasing the divisional logistical com

Combat elements in the division declined by 6 percent from 19

headquarters elements increased by 2 percent and logistical elem

4 percent. The biggest change in the division’s logistical struct

the expansion of the divisional ordnance (i.e., maintenance) comp

battalion and the addition of a replacement company, whose streng

fluctuate from 41 to over a thousand, depending on the replacemen

of the division.27 

In July 1953, the US Army fielded a total force of 20 di

including the 7 in Korea. Table 3 shows the slice of the entire Ar

the divisions represented. In comparison to World War II, the ope

slice had risen 3 percent from 67,900 to 76,607. Reflecting the 

of formerly nondivisional elements into divisional structure, 

divisional elements now reflected 25 percent of the operational 

opposed to 20 percent in World War II. 

Table 3. Korean War US Army Operational Slice28 

a. b. c. d. e. f. 

Total Number of Standardized Standardized Operational Operational Division Non- 

Strength Divisions Division Slice Percentage Divisional Div

Size (a/b) of the Army Slice Per

(c/d) (d - c) of t

1,533,815 20 18,804 76,691 25 57,887 

Vietnam War 

Beyond doubt, the US forces in South Vietnam from 1965 

maintained a large infrastructure. But was this infrastructure so h

the tooth-to-tail ratio was as high as is often claimed? Such ass

almost always unsupported by data, generally range from 1 to 4 

by former Vice President Al Gore’s biographer Bob Zelnick to V

veteran and military analyst David Hackworth’s 1 to 11, with the pro

of 10 support troops for every combat trooper as the most common

figure.29 

Do such high noncombat ratios stand up to scrutiny? Based on 

by-unit analysis, in April 1968, US Army units in Vietnam cons

28 
1st LOG

Cited battalions are battalion equivale

1st LOG 1st Logistical Command

AC Air Cavalry ADA Air Defens

ADV Advisors AG Adjutant Ge

AV Aviation ENG Engineers

FA Field Artillery MED Medical

MI Military Intelligence MP Military Poli

MT Maintenance ORD Ordnance

S&S Supply and Service SC Signal Corp

SPT Support TC Transportat

AV 6 TC 1

SPT 11 MI 1

S&S 3 ORD 1

MED 5 MP 1

FA 7 ADA 1

AG 6

AV 7

S&S 19

MT 7

MED 5

HOSPITALS 27

TC 33

ORD 5

MACV

SC 

MP 

ENG 

AG 

USARV

1st LOG

SF

ADV

1st LO

1st LOG

MACV

USARV

1st LOG

33,618 of these troops would have been serving in a combat capac

there were seven divisions deployed in the country (and the eq

of one and two-thirds more in separate brigades.) Even exclud

nondivisional combat troops, this results in each division fi eldi

4,802 combat troops. However, the typical infantry division 

Vietnam, organized under the Reorganization Objective Army D

(ROAD) configuration (Figure 19) consisted of about 16,902 s

The Army reconfigured infantry divisions deployed to Vietnam 

“light” structure, which deleted much of the heavy equipment foun

division’s logistics tail and its combat elements, while adding ad

Based on the table of organization, the combat component 

divisions, while not as high as the World War II division’s 68 perce

Korean War’s 62 percent, was approximately 9,769 troops or 58 

of the divisional totals. Accordingly, the 7 divisions alone accou

roughly 68,383 combat personnel. Within the division, headquarte

accounted for 31 percent and logistical elements were 11 percen

total personnel based on function (Figure 20).30 

Consequently, with over double the number of combat troops 

versus 33,618), the functional tooth-to-tail ratio in Vietnam in Ap

companies and battalions to its infantry component. 

Figure 19. Vietnam War Theater Organization, 1968. 

HEADQUARTERS

CATEGORY- PRIMARY MISSION

COMBAT LOGISTICAL

XXX

x3

+ +

=

= =

= =

= =

= =

= =

= =

= =

= =

III

x37*

I I

x48

I I

x109

AV 12

AC 5

FA 26

ADA 5

XXXXX

I I

x89 AV 26 MI 10

AG 2 TC 26

MT 10 ORD 4

MED 4 MP 7

I I

X

x4

X X

x5

X X

x2

XXXX

III

LIFE SUPP

* INCLUDES BRIGADE AND SUPPORT COMMAND HEADQUARTERS

+ + + +

HEADQUARTERS 

CATEGORY- PRIMARY MISSION 

COMBAT LOGISTICAL 

XXX

x3 XXX x3 

+ + 

1st LOG 

Cited battalions are battalion equivale

1st LOG = 1st Logistical Command 

AC = Air Cavalry ADA = Air Defens

ADV = Advisors AG = Adjutant Ge

AV = Aviation ENG = Engineers 

FA = Field Artillery MED = Medical 

MI = Military Intelligence MP = Military Poli

MT = Maintenance ORD = Ordnance 

S&S = Supply and Service SC = Signal Corp

SPT = Support TC = Transportat

AV 6 TC 1 

SPT 11 MI 1 

S&S 3 ORD 1 

MED 5 MP 1 

FA 7 ADA 1 

III

x37* III x37* 

AG 6 

AV 7 

S&S 19 

MT 7 

MED 5 

HOSPITALS 27 

TC 33 

ORD 5 

I I

x48 II x48 

I I

x109 II x109 

AV 12 

AC 5 

FA 26 

ADA 5 

XXXXX

MACV 

I I

x89 II x89 AV 26 MI 10 

AG 2 TC 26 

MT 10 ORD 4 

MED 4 MP 7 

I III 

SC 

MP 

ENG 

AG 

X

x4

X 

x4 

X X

x5

XX 

x5 

X X

x2

XX 

x2 

XXXX 

USARV 

I I I I I I 

LIFE SUPP

* INCLUDES BRIGADE AND SUPPORT COMMAND HEADQUARTERS 

+ + 

1st LOG 

SF 

ADV 

+ + 

1st LO
LRRP

MAINT

S& T

MP

ADMIN

DISCOM

LRRP

MAINT

S& T

MP

ADMIN

DISCOM

Figure 20. Vietnam War Infantry Division Organization. 

HEADQUARTERSCOMBAT LOGISTICAL

X X

X

x3

I I

x10

I I

x4

I I

I I

DIVISION

ARTILLERY

I

I I

I I

I

I I

I

DISCOM = Division Support Comman

LRRP = Long Range Reconnaissance 

S & T= Supply and Transportation

I I

I I

I I

attached

HEADQUARTERS COMBAT LOGISTICAL 

X X 

X

x3 X x3 

I I

x10 II x10 

I I

x4 II x4 

I I 

I I 

DIVISION

ARTILLERY

DIVISION 

ARTILLERY 

I 

LRRP 

I I 

MAINT 

I I 

S& T 

I 

MP 

I I 

I 

ADMIN 

DISCOM = Division Support Comman

LRRP = Long Range Reconnaissance 

S & T= Supply and Transportation 

DISCOM 

I I 

I I 

I I

attached

II 

could not be as high as 1 to 10. Divisional combat troops alone ac

for 22 percent of the total force in the country, a ratio of 3.5 to 

from the divisions, additional combat troops were found in four 

infantry brigades, an armored cavalry regiment, a large theater 

brigade, nondivisional artillery battalions and in small units assi

necessary to support other combat units. There were also over 9,0

sors supporting the combat units of the Army of the Republic of V

(ARVN). These additional troops totaled 51,044, giving Vietnam 

of 113,030 Army combat personnel in April 1968. This number 

percent of the 324,030 Army troops deployed in the country at th

Such a proportion produced a functional tooth-to-tail ratio of slig

than one combat soldier to every two support troops (Figure 21). 

Figure 22 depicts the proportion of forces by primary function 

Vietnam in April 1968. Of the 65 percent, or slightly less than tw

of the total portion involved in noncombat roles, headquarters too

lion’s share, 30 percent of the whole and 46 percent of the noncom

ments. While it is often difficult to distinguish life support functio

logistical ones, the 12 percent cited as life support includes engine

devoted to construction tasks, signal infrastructure units and mili

lice elements devoted to running prisons and stockades for friendly 

Logistics organizations formed almost a quarter of all theater troo

Compared to the Korean theater, the Vietnam theater, while h

percent more combat troops, retained roughly the same ratio of 

troops to noncombat troops (1 to 2). However, the mix of noncom

30 
11% 

31% 

Combat

Logistics

HQ/Admi

Combat 

Logistics 

HQ/Admi

58% 

Figure 21. ROAD Light Infantry Division, Vietnam 1968.31 

23% 35% 

30% 

Combat

Logistics

HQ/Admin

Life Suppo

Combat 

Logistics 

HQ/Admin 

Life Suppo

12% 

Figure 22. US Army, Vietnam, April 1968.32 

ments had changed. Headquarters elements continued their trend 

pansion, increasing 4 percent from Korea (and 14 percent from t

in World War II). Life support elements increased in Vietnam by 6 

from Korea. Much of the increase in life support was seemingl

expense of logistical elements. This may indicate the blurred line b

these two elements, rather than an actual decline in logistical elem

cause of a life support increase. Overall, logistical and life support 
a decrease from 42 percent in Korea and 45 percent in World War 

decrease is accounted for by a concurrent increase in headquart

ments. 

In 1968, the US Army fielded 19 divisions, of which 7 

Vietnam. Additionally, there were six separate combat brigades, 

the equivalent of two more divisions. Table 4 shows how the d

compared to the total size of the Army. The resulting operational 

74,778 is roughly 1 percent less than the equivalent figure from the 

War. The percentage of divisional elements in the slice decreas

percent as well.33 

Table 4. Vietnam War US Army Operational Slice.34 

a. b. c. d. e. f. 

Total Number of Standardized Standardized Operational Operational Division Non- 

StrengthStrength Divisions Division Slice Percentage Divisional Div

Size (a/b) of the Army Slice Per

(c/d) (d - c) of t

1,570,343 21 16,475 74,778 22 58k,303 

The Cold War Era, 1974 

The Nunn Amendment 

As the Cold War confrontation with the Soviet Union evolv

an extended stand-off, occupation forces in Germany and Japan 

defensive forces. During the Vietnam War, the demands for tro

equipment in Southeast Asia partially depleted the US units in G

At the same time, however, the Soviets conducted a unilateral bui

their forces in central Europe. They had upgraded all their tanks t

models and increased the number of tanks in their motorized rifle di

At the same time, five tank divisions were added to the troops 

against North Atlantic Treaty Organization (NATO) units. Along w

numerical increase, the 1968 Warsaw Pact invasion of Czechos

caught NATO planners and intelligence analysts by surprise. It 

that the Soviets were building up for a surprise attack in Germany. 

signs of renewed Soviet aggressiveness were apparent in Kremlin 

to intervene in the crisis precipitated by the 1973 Yom Kippu

32 
TASCOM

Cited battalions are battalion equivalen

TASCOM Theater Army Support Command

ADA Air Defense Artillery AG Adjutant Gener

AV Aviation CEG Combat Equip

ENG Engineers FA Field Artillery

FIN Finance NF Infantry

MED Medical MI Military Intellige

MP Military Police MT Maintenance

ORD Ordnance PSOP Psychologic

SF Special Forces S&S Supply and Se

SC Signal Corps SPT Support

TC Transportation Corps

AV 1 TC 2

SPT 3 MI 4

ORD 15 MED 1

MP 6 AG 1

FA 13 ADA 4

SC 27 QM 2

ENG 10

AG 6

AV 4

S&S 3

MP 1

MT 14

MED 4

HOSPITALS 16

TC 12

ORD 8

ENG 3

FIN 3

AV 3

INF 1

FA 27

ADA 17

SF 1

USAR

& 7A

AV 3 MI 8 MT 10

AG 1 TC 5 ORD 5

MED 3 MP 4 SC 15

SPT 2 QM 1 PSOP 1

ENG 4

TASCOM

CEG

DEPOTS

X

x2

1976 TASCOM

MERGED

WITH

USAREUR

1976

r

TASCOM CEG

DEPOTS

signs of renewed Soviet aggressiveness were apparent in Kremlin 

to intervene in the crisis precipitated by the 1973 Yom Kippur Wa

Therefore, new emphasis was placed on the American groun

in Germany. Four combat divisions (two armored, two mechanize

try), two separate brigades and two armored cavalry regiments h

stationed there since the 24th Infantry Division (Mechanized) h

transferred to Fort Riley in 1968. With Army troops in German

1945, a large support structure had built up over the years. Figure 2

the Army forces in Germany in 1974 and 1976 by functional categ

HEADQUARTERS

CATEGORY- PRIMARY MISSION

COMBAT LIFE S

XXX

x2

+ +

=

= =

= =

= =

= =

= =

= =

= =

= =

= =

=

III

x89*

I I

x49

I I

x74

XXXX

EUR

I I

x62

I 

x2

* INCLUDES BRIGADE AND COMMAND HEADQUARTERS

X X

X X

x2

X

x1

X

x1

III

x2

+ +

III

x8

LOGISTICAL

N

XXX 

+ + 

TASCOM 

III 

USAREUR 

& 7A 

I I 

HEADQUARTERS 

CATEGORY- PRIMARY MISSION 

COMBAT LIFE S

x2 

Cited battalions are battalion equivalen

TASCOM = Theater Army Support Command 

ADA = Air Defense Artillery AG = Adjutant Gener

AV = Aviation CEG = Combat Equip

ENG = Engineers FA = Field Artillery 

FIN = Finance NF = Infantry 

MED = Medical MI = Military Intellige

MP = Military Police MT = Maintenance 

ORD = Ordnance PSOP = Psychologic

SF = Special Forces S&S = Supply and Se

SC = Signal Corps SPT = Support 

TC = Transportation Corps 

AV 1 TC 2 

SPT 3 MI 4 

ORD 15 MED 1 

MP 6 AG 1 

FA 13 ADA 4 

SC 27 QM 2 

ENG 10 

x89* 

AG 6 

AV 4 

S&S 3 

MP 1 

MT 14 

MED 4 

HOSPITALS 16 

TC 12 

ORD 8 

ENG 3 

FIN 3 

I I

x49 II x49 

I I

x74 II x74 

AV 3 

INF 1 

FA 27 

ADA 17 

SF 1 

XXXX 

x62 

AV 3 MI 8 MT 10 

AG 1 TC 5 ORD 5 

MED 3 MP 4 SC 15 

SPT 2 QM 1 PSOP 1 

ENG 4 

I I

x2 

* INCLUDES BRIGADE AND COMMAND HEADQUARTERS 

X X 

X X

x2

XX 

x2 

X

x1

X 

x1 

X

x1

X 

x1 

III

x2 III x2 

++ 

TASCOM 

III 

CEG 

DEPOTS x8 

LOGISTICAL 

X

x2

X 

x2 

1976 TASCOM 

MERGED 

WITH 

USAREUR 

1976

N

r

Figure 23. Germany 1974 and 1976 Organization. 

As part of the Army’s post-Vietnam reduction and conversio

all-volunteer force, members of Congress expressed some concern

the post-drawdown tooth-to-tail ratio.37 Congress had the consti

responsibility to authorize the armed forces’ budget. It typically u

responsibility as a means to provide oversight of the armed for

often attached specific provisions as amendments to the act appro

budget. In 1974, when members of the US Congress looked at the 
headquarters elements in comparison to its combat elements. Sena

Nunn of Georgia sponsored and Congress passed a provision spe

designed to correct this perceived deficiency for the Fiscal Year 

budget which stated “the non-combat component of the total Unite

military strength in Europe authorized as of June 30, 1974, shal

duced by 18,000.” The Army’s share of this total was 12,175. The 

ment also allowed the Army to replace the noncombat compone

combat elements. These were defined in particular as battalion-si

of infantry, armor, field artillery, air defense artillery, cavalry, en

special forces, and aviation.38 

According to the Army’s Active Army Troop List, dated 31 

1974, there were 186,822 troop positions authorized in German

allotment of soldiers consisted of an authorized 51,170 comba

(27 percent), 70,455 headquarters or headquarters support person

percent) and 65,094 positions (35 percent) for logistical or life 

type positions (Figure 24).39 

35% 

38% 27% 

Life Supp

HQ/Admin

Combat

Logistics/

Life Supp

HQ/Admin 

Combat 

Logistics/ 

Figure 24. US Army in Germany, March 1974. 

Congress required reductions in the 73 percent which did not 

of combat elements. The Nunn Amendment allowed for two co

action: the elimination of the 12,175 noncombat positions outright 

replacement by combat positions. Both actions had to be complete

2 years. Naturally, the Army chose the latter and instituted the sho

Brigade-75 and Brigade-76 programs to produce the lion’s shar

positions.40 With these two choices, the Nunn Amendment’s pro

34 
Total

Non-Co

Combat

29 and 34 percent of the total organization in Europe (Figure 2

yielded ratios between combat and noncombat forces of 1 to 2.4 

1.9. Congress, accordingly, in 1974 considered an acceptable toot

ratio to be roughly two noncombat soldiers for every combat sold

Figure 25. The Nunn Amendment Tooth-to-Tail Ratio. 

0

20

40

60

80

100

120

140

160

180

200

1974

NUNN

REDUCTIONS

NUNN

REDUCTIONS W/

CBT PLUS UP

73%

29% 34% 27%

71% 66%

THOUSANDS OF TROOPS

0 

20 

40 

60 

80 

100 

120 

140 

160 

180 

200 

Total 

Non-Co

Combat 

1974 

NUNN 

REDUCTIONS 

NUNN 

REDUCTIONS W/ 

CBT PLUS UP 

73% 

29% 34% 27% 

71% 66%

THOUSANDS OF TROOPS 

There is no direct indication as to how Congress determined it

to-tail ratio. It seems to have been a combination of factors. The 

the Soviet threat in central Europe drove much of the discussion. A

Vietnam drawdown, it seemed essential to get the most combat po

of the available manpower. Congressional reports produced in 1

1974 also made it clear that Congress was most concerned with 

saw as a proliferation of headquarters organizations. A third, and p

key point, was that at the height of the Vietnam deployment, as pre

discussed, combat troops made up 36 percent of forces, a high

of combat troops than the 27 percent found in Germany in 19

even higher than that required by the Nunn Amendment’s top fig

percent). The difference in figures may be ascribed to a greater n

life support in Germany. Unlike in Vietnam, many families of 
MAINT

S& T

MP

DISCOM ADMIN

FIN

MAINT

S& T

MP

DISCOM ADMIN

FIN

facilities. These facilities required a proportion of support that 

been necessary in Vietnam.41 

ROAD Armored Division 

The 1974 Cold War Army still used the ROAD structure, as em

in Vietnam. While most of the units in Vietnam were light infantry di

the divisions in Germany either were all mechanized infantry or a

For the sake of this work, the Vietnam infantry division was compa

the 1974 ROAD armored division. Figure 26 categorizes the di

elements. Figure 27 shows this armored division proportionally 

into combat, logistical and headquarters categories. With attachm

combat, usually aviation elements, the Vietnam divisions were 1,84

than their counterparts in Germany. Additionally, while 1968 V

divisions usually had 11 combat battalions (10 infantry and 1 c

and the two 1974 armored divisions in Germany had 12 combat ba

(6 tank, 5 mechanized infantry, 1 cavalry), the combat slice in t

division was smaller by 3,059. Some of these differences may be ac

for by the difference in size between tank units and infantry uni

battalions were only about two-thirds of the size of infantry battal

expected of a unit equipped largely with mechanized vehicles, lo

CATEGORY- PRIMARY MISSION 

HEADQUARTERS COMBAT LOGISTICAL 

X X I I I I 

I I

x4 I I

I I

DIVISION

ARTILLERY

I I

I I

I

I

DISCOM = Division Support Co

FIN =Finance

Chap = Chaparral

S & T = Supply and Transporta

I I

I

I I

x5

x6

X

x3

I I VULCAN/

CHAP

I I I

x4

II 

x4 I I 

I I 

DIVISION

ARTILLERY

DIVISION 

ARTILLERY 

I I 

MAINT 

I I 

S& T 

I 

MP 

I 

ADMIN 

DISCOM = Division Support Co

FIN =Finance 

Chap = Chaparral 

S & T = Supply and Transporta

DISCOM 

I I 

I 

I I

x5 II x5 

x6 

X

x3 X x3 

I I VULCAN/

CHAP

II VULCAN/ 

CHAP 

I 

FIN 

Figure 26. Armored Division Organization, 1974. 

36 
35% 

20% 

Combat

Logistics

HQ/Admi

Combat 

Logistics 

HQ/Admi

45% 

Figure 27. ROAD Armored Division, 1974. 

personnel account for most (9 percent) of the 13 percent differ

combat strength between the Vietnam division and the 1974 organ

However, not all of the difference consists of logistical elemen

percent of the difference was in a proportional increase in the 

headquarters. Of course, logistical elements had their own head

units to control their operations.42 

In a comparison with the 1943-45 armored division, the 

1974 armored division was 40 percent larger with 4,369 ad

personnel spaces. But within these additions, the combat elem

been proportionally reduced by 13 percent, while the headquarte

increased by 14 percent. Even though World War II armored d

only had 6 combat maneuver battalions (3 tank and 3 armored i

compared to 11 (6 tank and 5 mechanized infantry) in the ROAD d

the larger battalions in the World War II division totaled 2,736 

positions as opposed to 4,237 combat slots in the 1974 counterp

a 120 percent increase in the number of maneuver battalions, the 

division only contained a 55 percent augmentation in combat troo

ROAD division was organized into smaller units with a prop

increase in headquarters elements and decrease in combat position

The Nunn Amendment related to the operational slice. It ul

ended up being an attempt to increase the number of division equ

in the force structure without expanding the overall strength 

organization. Between 1974 and 1976, the Army did increase its 
Table 5 shows the operational slice for 1974 and 1976. The origin

condemned by Congress, was actually smaller by almost 17,000 

equivalent of one division) than the equivalent figure during the V

and Korea eras. The percentage of the slice containing divisiona

was actually 6 percent higher than during the Vietnam War and 3 

higher than that of Korea. By 1976, the Army had expanded to 16 di

This expansion was done largely by merely moving some logist

combat elements to the reserve components. Nevertheless, the ope

slice was reduced by almost 11,000 troops, with the proportion 

Army found in combat divisions being increased by 6 percent. H

many senior Army officials felt the tail had been reduced below m

levels. In 1980, General Edward Meyer, the then Army Chief of Sta

referred to the Army at the time in a famous comment as being “h

referring to deficiencies in equipment, manning and modernizatio

Table 5. Cold War, 1974 US Army Operational Slice 

a. b. c. d. e. f. 

Total Number of Standardized Standardized Operational Operational Division Non- N

StrengthStrength Divisions Division Slice Percentage Divisional Divi

Size (a/b) (c/d) Slice Perc

(d - c) of the 

(f

783,330 13.5 16,475 58,024 28 41,549 

779,417 16 16,475 48,714 34 32,239 

The Congressional foray into the tooth-to-tail ratio, asid

establishing a general mandate of 34 percent combat troops, also p

one of the first realizations that headquarters units, even those head

commanding combat troops, were not part of the tooth, but 

Despite this realization, when the Army conducted its next maj

structure reorganization, the Division 86/Army of Excellence P

headquarters elements were increased, not decreased. While prov

interesting look at the T3R and the only publicly prescribed m

ratio in the modern era, the Nunn Amendment seemed to have no 

effect on the way Army force planners designed units. 

38 
Starting in the late 1970s, with the projected fielding of new w

systems including the M1 tank, the M2 infantry fighting vehicle 

AH-64 Apache attack helicopter, US Army force planners began 

at an organizational structure to replace the ROAD confi guratio

redesign was originally called “Division 86” and then later, when e

to the Army as a whole, as “the Army of Excellence.” In redesig

division, Army planners were given an operational concept, wh

projected to produce the following rough ratio between its compo

a division about 17,500 in size: combat—77.5 percent, headquarte

percent, and logistics—12.8 percent.45 

Planners only classified the division and brigade head

companies and the signal battalion as headquarters element

elements in combat battalions and in logistical units were con

to be combat and logistical elements. Accordingly, a direct com

with the ROAD structure is not possible. Discounting headquar

logistical elements in combat battalions and headquarters elem

logistical units, a ROAD division possessed 45 percent of its 

in combat elements, 35 percent in headquarters elements and 20 

in logistical elements. One thing is clear from the Division 86 p

guidance: logistical elements, already smaller than under ROA

including their headquarters units, were projected to be streamline

new organization. 

Army force developers also accounted for an additional 

nondivisional combat and combat service support elements des

to support each division. Of this total 47,000-troop package, di

elements were projected to form 37 percent.46 

The Division 86/Army of Excellence (AOE) reorganizatio

through many permutations before the first divisions converted to 

configuration in 1983. While the AOE reorganized all the types of d

found under ROAD (infantry, light infantry, air assault, airborne, a

and mechanized infantry), this work focuses on the armored division 

28) because it was the most common type of division used in D

STORM, the case study for the employment of the AOE structu

nutshell, the reorganization removed support elements from the c

level in maneuver combat battalions while adding combat power 

addition of a company to each tank and mechanized infantry battal

two additional cannons to each field artillery howitzer battery. An 

brigade was also added to each division with one or two attack he

battalions and other aviation elements. Concurrently, divisional 
MSB

FSB

MP

ADMIN

DISCOM

NBC

CEWI

AVIM

MSB

FSB

MP

ADMIN

DISCOM

NBC

CEWI

AVIM

HEADQUARTERS

CATEGORY- PRIMARY MISSION

COMBAT LOGISTICAL

I I

x3

I I

I I

DIVISION

ARTILLERY

I I

I I

I

I I I

I

X X

I I

x4

I I

x6

X

x3

I I

I

I I

X

I

I

I I

x2

I

DISCOM = Division Support Command

CEWI = Combat Electronic Warfare & I

FSB = Forward Support Battalion

MSB = Main Support Battalion

NBC = Nuclear, Biological, Chemical

AVIM = Aviation Intermediate Maintena

HEADQUARTERS 

CATEGORY- PRIMA

I I 

DISCOM 

X 

RY MISSION 

COMBAT LOGISTICAL 

I I

x3 II x3 

I I 

DIVISION

ARTILLERY

DIVISION 

ARTILLERY 

I I 

MSB 

I I 

FSB 

I 

MP 

I 

ADMIN 

I I 

I 

X X 

I I

x4 II x4 

I I

x6 II x6 

x3 

I I 

I 

NBC 

I I 

CEWI 

X 

I 

I 

I I

x2

II 

x2 

I 

AVIM 

DISCOM = Division Support Command 

CEWI = Combat Electronic Warfare & I

FSB = Forward Support Battalion 

MSB = Main Support Battalion 

NBC = Nuclear, Biological, Chemical 

AVIM = Aviation Intermediate Maintena

Figure 28. Armored Division Organization, 1986. 

support elements were streamlined into multifunctional units g

specifically to support particular division combat elements.47 

Figure 29 shows the functional T3R in the AOE armored divis

was finally fielded in 1986. With roughly the same number of pe

the new organization increased the combat portion of the divisi

percent, while reducing the headquarters portion by 10 percent, 

the addition of the aviation brigade headquarters. Logistics increa

percent. This could be credited at least partially to increased main

and supply requirements for the newly fielded equipment such as 

tank. Additionally, the increase in helicopters in the division broug

it increased aircraft maintenance requirements. At the division le

Army of Excellence program successfully streamlined the divisio

External to the division, combat service support assets we

reorganized. Most corps-level service support units were organi

corps support groups (CSG) which controlled nondivisional lo

units within a geographical area. For the most part, one CSG wa

with each division as part of a concept called “fix forward,” which 

nondivisional direct support and general support logistical a

40 
25% 

26% 

Combat

Logistics

HQ/Admi

Combat 

Logistics 

HQ/Admi

49% 

Figure 29. AOE Armored Division, 1986. 

forward into the division’s rear area. CSGs organized most of their 

operations under multifunctional corps support battalions (CSB), w

direct support CSB working in the division area. Some logistical u

worked under the older functional (i.e., single type of support) co

particularly medical and transportation.49 

The DESERT STORM campaign in early 1991 was the firs

the AOE organizational structure. For the operation, the Army d

a field army headquarters, two corps headquarters and the equiv

seven divisions, along with extensive combat support and combat 

support assets at the corps, army and theater levels. The total Army 

the theater of 333,565 represented 58 percent of Active Army stren

the deployed divisions were slightly less than half of the Army’s di

force structure. It was the Army’s largest deployment since Vietn

the fastest expeditionary build up in US history.50 

Figure 30 depicts the functional tooth-to-tail ratio for the 

Theater of Operations (KTO) at the end of the ground war portio

campaign. While in each of the seven combat divisions deploye

KTO, the ratio between combat to noncombat elements was 1 t

overall KTO ratio was 1 to 3.3. The difference between the AOE 

(Figure 17) and the theater as a whole consisted of increased headqu

percent) and logistics/life support (16 percent) elements. The exped

nature of the operation and the large number of forces may acc

the increased logistics/life support proportion. A major proportio
28% 

42% 

30% 

Life Suppo

HQ/Admin

Combat

Logistics/

Life Suppo

HQ/Admin 

Combat 

Logistics/ 

Figure 30. Kuwaiti Theater of Operations (KTO), March 1991

logistical piece was found in medical units, as US planners expecte

casualties. Surprisingly, the headquarters element was 10 percent 

than in Cold War Germany (Figure 11) and the logistics/life support 

was 7 percent higher. The latter statistic may be partially accounte

the large amount of host nation support available to logistical elem

Germany.51 

However, the proportions in the KTO are not that differe

the ratios in the previous similar US Army expeditionary operat

deployment to Vietnam (Figure 22). In Vietnam, combat troops 

percent of the total, while the KTO figure was a decrease of 5 

Headquarters elements decreased by 2 percent in the KTO dep

compared to Vietnam, while logistical/life support elements in

from Vietnam to the KTO operation by 7 percent. 

Some Army officers, particularly logisticians, feared that the 

the post-Nunn Amendment era had been tilted in favor of comba

to an extent where the logistical forces had become a “thin line . . 

the combat forces.”52 In 1987, LTC John Vann observed negativ

Army logistical unit levels had never been restored to the level

and during Vietnam, and had actually declined. The operational sli

1991 (Table 6) clearly reflects Vann’s assessment. Army wide, th

at 39,046, was the lowest it had ever been since the Army fiel

division as its basic operational unit. This meant that divisions too

largest proportion of Army strength ever since World War I at 44 

However, the slice for the divisions deployed to Southwestern A

42 
a. b. c. d. e. f. 

Total Number of Standardized andardized Operational Operational Division Non- N

StrengthStrength Divisions Division Slice Percentage Divisional Div

Size (a/b) (c/d) Slice Perc

(d - c) of th

(

Worldwide 

572,423 14.66 17,104 39,046 44 21,945 

DESERT STORM 

333,565 7 17,104 47,652 36 30,548 

DESERT STORM was 5 percent and 8,606 soldiers higher. This r

the Army’s deployment of a larger proportion of nondivisional f

SWA than was normally found overall, with divisions forming 37 

of the Gulf force, while they formed 44 percent of the Army as a w

The Modular Army and the New Millennium 

After DESERT STORM, the Army retained the AOE s

throughout the 1990s, tweaking it primarily by removing 

companies from mechanized infantry battalions, deleting one of 

companies from the tank and mechanized infantry battalions, and 

an engineer battalion and a motorized reconnaissance troop 

brigade. In the latter part of the decade, the perceived impact o

communications resulted in the development of a streamlined ve

the AOE called Force XXI. The primary distinctive feature of th

XXI concept was that logistical activities were consolidated in the 

the division support command (DISCOM). Digital communicatio

considered capable enough of tracking logistical needs to allow 

consolidation of the traditional unit and direct support echelons of 

service support and most logistical elements were deleted com

from combat battalions. The Force XXI changes were not com

implemented, only being fielded in one division and parts of a 

before the program was supplanted with the modular Army conce

Unlike the AOE change, which was basically a streamlined ve

the ROAD structure, the shift to the modular structure in the early 

the new millennium was a conceptual shift from the division to the 

as the basic operational organization. The development of the b

based Stryker program was its direct precursor. 
The modular Army had its origins in the development of the 

Brigade. The creation of Stryker units began in 1999 as the lat

series of Army attempts to develop an acceptable light armored w

vehicle to equip infantry units. Such a vehicle gave infantry muc

of the firepower and survivability inherent in heavy (mechanized 

and armored) units while retaining most of the strategic mobility 

infantry units. The program soon developed the Stryker combat 

as its basic piece of equipment. The biggest departure from the p

the use of the brigade, rather than the division, as the basic ope

unit in the Stryker program. While most Stryker brigades 

divisional designations, the brigades were organized as complete

contained units with all the supporting divisional elements being 

the organization (Figure 31). For this reason, the brigades were 

referred to as brigade combat teams (BCT). Reinforcing this notio

early 2007, no Stryker brigade had yet been employed operational

its titular division headquarters. 

HEADQUARTERS

CATEGORY- PRIMARY MISSION

COMBAT LOGISTIC

SPT = Support

MI = Military Intelli

I I

x3

X

I I

I

I I

SPT

I I

I

MI

I

I

HEADQUARTERS 

CATEGORY- PRIMARY MISSION 

COMBAT LOGISTIC

SPT = Support 

MI = Military Intelli

I I

x3

II 

x3 

X 

I I 

I 

II 

SPT 

II 

I 

MI

I

MI 

I 

I 

Figure 31. Stryker Brigade Organization, 2004. 

Stryker brigades used the digital packages developed for Force 

enhance their fighting and command and control capabilities. Acco

the headquarters elements in the Stryker brigades were reduced by 7 

44 
split almost in half between the brigades logistical and combat el

with combat forces increasing by 3 percent and logistical elemen

percent. The ratio between combat and noncombat elements is sh

Figure 32. 

18% 

30% 

Combat

Logistics

HQ/Adm

Combat 

Logistics 

HQ/Adm

52% 

Figure 32. Stryker Brigade, 2004. 

Modular Brigades 

As early as 2002, the Army began developing plans to exp

Stryker organizational structure to the rest of the Army. Starting 

2004, these designs were implemented in a construct known 

modular Army. The modular Army changed the basic operatio

from the division to the brigade, but did not remove the divisio

the organizational structure. Under modularity, divisions acted p

as command and control headquarters with their subordinate e

tailored based on the division’s mission. However, when AOE d

converted to the new structure, most of the former divisional e

remained under their old division. This gave a notional modular 

organization as shown by category in Figure 33. 

Such a division consisted of a division headquarters, four co

arms brigades (from the division’s three former maneuver brigad

one each of the following: a fires brigade (the former division 

headquarters with a multiple rocket launcher system (MLRS) b

an aviation brigade (former divisional aviation brigade); a reconna
I I

MI x1-3

I I

x1-3

I I

I I

x1-2

I I

SPT 

SUST

CS I I

x1-2

I I

I I

CA

MI

CS

HEADQUARTERSCOMBAT LOGISTIC

XX X

x4 X

X X

X

X

MI = Military Intelligence

CS = Combat Support

SUST = Sustainment

SPT = Support

HEADQUARTERS COMBAT LOGISTIC

XX X

x4 X x4 X 

X 

I I

x1-3 II 

MI 

I I

x1-3 II x1-3 

X 

I I

I I

x1-2

II 

II 

x1-2 

X II 

SPT 

SUST 

X 

CS I I 

x1-2 

I I 

I I 

CA 

MI = Military Intelligence 

CS = Combat Support 

SUST = Sustainment 

SPT = Support 

Figure 33. Notional Modular Division Organization, 2004. 

surveillance, and target acquisition (RSTA) brigade (an expansio

former divisional military intelligence battalion); a sustainment 

(the former division support command headquarters with divisi

support elements); and a combat support or maneuver enhan

brigade (containing former divisional elements such as the air 

artillery (ADA) and engineer battalion and an expanded nuclear, bio

chemical (NBC) company).54 

The notional modular division, containing almost all the e

found in the AOE division, was larger by 5,127 positions, an increa

percent. Headquarters elements formed more than half (56 percent

increase, while most of the rest (41 percent) was an increase in lo

elements. A task-organized modular division was slated to be eve

with additional battalions typically attached to the brigades (Figur

Because it was a system based on brigades, that echelon wa

the modular concept. The modular nature of the concept was the 

to employ, organize and move around Army operational force

on standardized brigade organizations, a smaller and therefor

operationally flexible unit than the division. The brigades were reor

into three basic types: light (light infantry), heavy (tanks and mec

infantry) and medium (the Stryker brigades that were being de

separately). Within these types, the brigades were also designe

46 
32% 

29% 

Combat

Logistic

HQ/Adm

Combat 

Logistic

39% 

Figure 34. Notional Modular Heavy Division, 2004. 

self-contained and interchangeable. The new modular brigades w

designed smaller than their equivalent predecessors as 36 AOE b

were to be converted to 48 modular brigades, a 25 percent increa

the same amount of troops. This increase was done primarily by r

only two maneuver battalions in the new organization’s strength o

As mentioned above, the heavy (mechanized infantry and arm

combined arms brigade contained most of the elements which the 

had routinely assigned to support the brigade in the AOE organ

This included two combined arms maneuver battalions contain

companies each of tanks and mechanized infantry, as well as an e

company and a dedicated support company. The brigade field artill

talion contained the minimum force to support the two maneuve

ions. There was also a small cavalry squadron in the brigade (Figu

The proportional relationships in the modular combined arms 

are shown in Figure 36. In relation to the AOE division, the smal

contained proportionally fewer combat elements (43 percent ver

Most of this difference matched a similar rise in logistical elem

percent versus AOE 26 percent). The new structure reduced head

elements by 1 percent. Therefore, in the modular brigades, the fu

T3R was 1 to 1.3 (combat to noncombat), a slight decline from 

1.02 ratio of the AOE division. At the divisional level, using the 

modular division as a model, the ratio was more drastically differ

to 1.6, versus the AOE’s 1 to 1.02. In any event, at the operatio
BSB

MI

BTB

I I

I

x2

I

x2

I

I

FSC

attached from BSB

I

I I

BSB

I

FSC

FA (Fires) 

I

FSC

Cav Sq

I

I I

FSC

Combined A

BSB

MI

BTB

FSC

BSB

FSC

FSC

FSC

HEADQUARTERSCOMBAT LOGISTICAL

I I

I I

I I

X

I

I

I I I I

x2

two firing batteries

BTB = Brigade Troops Battalion

BSB = Brigade Support Battalion

FSC = Forward Support Company

HEADQUARTERS COMBAT LOGISTICAL 

I I 

BSB 

I I 

II 

X

I

I

X 

I 

MI 

I 

I I 

BTB 

II 

x2 

I I two firing batteries

I

x2

I

x2

I

I

I I

I

x2

I

x2

I

I I 

I

x2

I 

x2 

I

x2 I x2 

I 

I 

FSC 

attached from BSB 

I 

I I 

BSB 

I 

FSC 

FA (Fires) 

I 

FSC 

Cav Sq

I 

I 

BTB = Brigade Troops Battalion 

BSB = Brigade Support Battalion 

FSC = Forward Support Company 

I 

FSC 

Combined A

Figure 35. Combined Arms Modular Brigade, 2004. 

24% 

33% 

Combat

Logistics

HQ/Adm

Combat 

Logistics 

43% 

Figure 36. Modular Combined Arms Brigade, 2004. 

(i.e., brigade) level, combat elements in the new millennium were 

removed from being on par with noncombat elements. 

As part of its adoption of the modular brigade as the basic ope

unit, the Army also instituted a program called Force Stabiliz

Unit Focused Stability. Unit Focused Stability supplanted the in

48 
manning life cycle at the brigade level. Once the system was imple

the cycle for each brigade would be 3 years, ensuring that brigade 

served together for that period. The Army coupled stabilizati

another new program called “home basing.” Home basing was d

to ensure that new soldiers remained at the same post for at leas

years when they joined the Army, except when deployed overse

two programs together were focused on the brigade as the stabili

home-based unit. 56 

Another characteristic of the modular organization was an ove

headquarters to structure them to match actual field employment

quarters at the brigade, division and corps levels were organized b

tion and most units considered in this work to be headquarters el

such as signal and military intelligence (MI) organizations, were 

dated under a headquarters or troops battalion. At the brigade le

former headquarters company was replaced by a brigade troops b

(BTB) of about 500 that included headquarters staffs for both the 

and the troops battalion, as well as an MI company and a signal co

Under the BTB’s brigade headquarters company, there were two co

posts (CP), a small tactical (TAC) CP and larger main CP, and a 

command group (MCG). The brigade commander headed the MCG

the newly created position of deputy commander headed the TAC 

the brigade executive officer (XO) the main CP. 57 

At the division level, with a staff of about 1,000 soldiers, a he

ters and headquarters battalion replaced the former HHC and w

nized around four command and control elements, two TAC CPs

CP and a MCG. The personnel in these command posts were or

under an HHC, while support personnel, such as cooks and vehi

chanics, were in a separate headquarters support company. A sig

security company filled out the battalion. At the corps level, troop 

was about the same as at the division at around 1,000. The head

was organized within a troops battalion and contained four head

elements, a MCG equipped with its own aviation assets, an Earl

Command Post (EECP), an operational CP and a main CP. The c

gistical commander headed the main CP and usually operated o

semipermanent fixed location. The EECP was a subcomponent of 

erational CP, acting as the advance party for that element. The ope

CP was the forward headquarters, while the MCG was the sma

centered on the corps commander. Corps headquarters were desi

command joint forces and, if necessary, to be the senior headquar

theater. 58 
unit, the portion of the Army found in the brigade is a significant 

tor of an operational T3R. Once all 48 active modular brigades are 

in late 2007, the projected brigade slice for the brigades would be 

(Table 7). Based on this figure, modular brigades were 36 percen

Army’s overall organizational structure. While this percentage is 

the percentage found during the Cold War in 1976 (34 percent) a

Nunn Amendment reforms, it is 8 percent less than the AOE Arm

figure from 1991 (44 percent). However, when AOE divisions w

ployed in 1990-91 to fight in the Gulf War, their support elemen

augmented, reducing the ratio to 36 percent, which matches exa

modular brigade slice percentage. 

Table 7. Modular Army Projected Brigade Operational Slice, 2007 

a. b. c. d. e. f. 

Total Number of Standardized andardized Operational Operational Brigade Non- 

StrengthStrength BrigadesBrigades Brigade Slice Percentage Brigade B

Size (a/b) (c/d) Slice Pe

(d - c) of 

500,000 48 3,735 10,417 36 6,682 

Since four modular brigades were roughly equivalent to the 

organizations used in previous divisional slices, using four brigad

produces a figure of 41,668, a total slice that is less than all di

slices cited in this work except for the Army-wide AOE slice fro

(39,046). 

Iraq and the Tooth-to-Tail Ratio 

In the ongoing Operation IRAQI FREEDOM, the Army emp

mix of Force XII, AOE, Stryker, and, in later stages, modular organi

Before the projected Baghdad surge of 2007, the highest US Arm

levels within Iraq, 135,000, were achieved in January 2005. Fi

shows the general organization of the forces in Iraq at that ti

Figure 38 depicts the functional T3R of the Army forces. W

counterinsurgency aspects of the Iraqi operation often place e

cited in this work as noncombat into combat situations, organ

whose primary mission was the conduct of combat operations cons

about 53,768 troops or 40 percent of the deployed force. Accordin

functional T3R was 1 to 2.5 (combat to noncombat). 

50 
COSCOM

TF

FA 2

MP 1

ENG 1

SG 7

MP 4

MED 2

TC 1

SPT 9

SC 2

COSCOM

X

X

VARIOUS

COMBAT

SERVICE

SUPPORT

UNITS

(Theater and

COSCOM

Levels)

28,000 C

CONTRA

VARIO

COM

SERV

SUPP

UNI

30,000 CIVILIAN

CONTRACTORS

TF

COSCOM

X

X

HEADQUARTERS

CATEGORY- PRIMARY MISSION

COMBAT LOGISTICAL

XX XX

x4

X

X

XXX + +

X X

I I

III

x5*

I I

x18

* INCLUDES BRIGADE AND COMMAND HEADQUARTERS

+ +

X

x3 X

Theater Defense

x15

AB INF 3

TK 1

FA 5

ENG 3

MP 2

AC 2

III

LIFE SU

TF = Task Force

COSCOM = Corps Support C

AB INF = Airborne Infantry

AC = Air Cavalry

FA = Field Artillery

MP = Military Police

MED = Medical

TC = Transportation Corps

ENG = Engineer

SG = Support Group

SC = Signal Corps

SPT = Support

TK = Tank

HEADQUARTERS 

CATEGORY- PRIMARY MISSION 

COMBAT LOGISTICAL 

XX XX

x4 

X 

X 

++ 

COSCOM 

XXX 

X X 

TF 

+ + 

COSCOM I I 

FA 2 

MP 1 

ENG 1 

SG 7 

III

x5* III x5* 

I I

x18 II x18 MP 4 

MED 2 

TC 1 

SPT 9 

SC 2 

* INCLUDES BRIGADE AND COMMAND HEADQUARTERS 

X 

x3 Xx3 X 

Theater Defense Theater Defense 

X 

X 

x15 

AB INF 3 

TK 1 

FA 5 

ENG 3 

MP 2 

AC 2 

III 

VARIOUS 

COMBAT 

SERVICE 

SUPPORT 

UNITS 

(Theater and 

COSCOM 

Levels) 

28,000 C

CONTRA

LIFE SU

VARIO

COM

SERV

SUPP

UNI

30,000 CIVILIAN 

CONTRACTORS 

TF = Task Force 

COSCOM = Corps Support C

AB INF = Airborne Infantry 

AC = Air Cavalry 

FA = Field Artillery 

MP = Military Police 

MED = Medical 

TC = Transportation Corps 

ENG = Engineer 

SG = Support Group 

SC = Signal Corps 

SPT = Support 

TK = Tank 

Figure 37. Iraq, January 2005. 

24% 

36% 

Combat

Logistics

HQ/Adm

Combat 

Logistics 

40% 

Figure 38. Army Forces in Iraq, January 2005. 
and was comparable to combat proportion in the ETO in World W

percent). It was a considerably higher proportion of combat troops 

Vietnam (35 percent) and Korea (33 percent) and the Nunn Ame

minimum acceptable level of between 29 and 34 percent. Ye

commentators have cited the extensive life support activities oc

concurrent with combat operations throughout Iraq.59 

It is difficult to cull life support elements from those conductin

tical activities. Unique from previous historical examples discusse

work, the extensive use of civilian contractors in Iraq has muddied 

ters in relation to the functional tooth-to-tail ratio. Estimates of the 

of contractors in Iraq in January 2005 vary. The commander of the 

major theater-level logistical organization cited a figure of 9,00

ians working in his organization and a total of 30,000 logistics con

working throughout Iraq. In Boots on the Ground, a total contracto

of 58,000 was used. That figure is retained here, divided for 30,000 

cal and 28,000 life support contractors.60 

Adding the 58,000 contractors to the functional T3R equation p

the pie chart depicted in Figure 39. The 58,000 are divided almos

between the logistical and life support categories. This increase 

by category in Figure 40) raises the overall logistical element lev

percent from 33, while reducing headquarters elements proportio

7 percent and combat elements by 12 percent. Contractor inclusio

Civilian 

Contractors 

31% 

Combat 

28% 

Logistics/ 

Life Support 

24%

HQ/ 

Admin 

17% 

Logistic

16% 

Life Supp

15% 

Figure 39. Army Forces in Iraq including Contractor Support, January 

52 
43% 

25% 

18% Combat

Logistics

HQ/Admin

Life Suppo

Combat 

Logistics 

HQ/Admin 

Life Suppo

18% 

Figure 40. Army Forces in Iraq including Contractor Support, 

Consolidated by Category, January 2005. 

separate life support category of 15 percent. This total, in fact, repr

minimum total for this category. An undetermined number of Arm

listed under the logistical category were undoubtedly primarily 

to life support functions as well. The 15 percent figure compare

percent in Korea in 1953 and 12 percent in Vietnam in 1968. 

However, similar to Korea in 1953, the Army maintained a l

gistical base nearby, in this case in Kuwait. Many theater support e

were located there instead of in Korea itself. Figure 41 shows th

tional T3R with the inclusion of the roughly 30,000 troops in 

Categorically, these forces consisted primarily of logistical elem

percent), but also included a sizable headquarters component (25 p

life support (7 percent) and combat (9 percent) elements. With the 

of the Kuwaiti theater base and contractors, the Iraq functional T3R 

a decline in combat elements below the Nunn Amendment level, w

a quarter of the force (a functional T3R of 1 to 3). 

Operationally, the division remained the basic unit in Januar

Accordingly, the operational slice is examined for Iraq, not the 

slice (Table 8). Overall, the Army fielded a force of 10 active d

in 2005, out of a total strength of 468,578. This equated to an ope

slice of 48,857 and an Army-wide percentage of divisional force

slightly more than a third of the Army. Focusing more narrowly 
41% 

28% 

17% 

Combat

Logistics

HQ/Admin

Life Suppo

Combat 

Logistics 

HQ/Admin 

Life Suppo

14% 

Figure 41. Army Forces in Iraq by Category, including Contractor Sup

Forces in Kuwait, January 2005.
 

Table 8. Iraq, January 2005, US Army Operational Slice61 

a. b. c. d. e. f. 

Total Number of Standardized andardized Operational Operational Division Non- 

StrengthStrength Divisions Division Slice Percentage Divisional Di

Size (a/b) (c/d) Slice Pe

(d - c) of 

Worldwide 

488,579 10 17,104 48,857 35 31,753 

Iraq, January 2005 

135,000 4 17,104 33,750 51 16,646 

54 
theater operational slice of 33,750. Accordingly, 51 percent, slight

than half, of the troops in Iraq were found in divisional organizati

Summary 

The historical examples cited in this chapter provide a series 

studies that can be readily compared and examined collectively to d

organizational trends, develop historically based force deve

estimates and provide an understanding of T3R development sinc

This analysis is presented in the next chapter. 
1. US War Department, The US Army in the World War, 1917-1919

1, “The Organization of the American Expeditionary Forces” (Washing

US Army Center of Military History, 1988), 144-5 [hereafter “The Orga

of the American Expeditionary Forces”]. 

2. The AEF maintained a force of nondivisional Corps of Engine

consisting of 241,613 troops, representing 12 percent of the total AEF fo

egorizing this force is problematic. I have chosen to place the whole engi

ment in the combat category, but undoubtedly, at least some of this force 

in the logistical category as the engineers also maintained the railroads. H

determining what portion of the 241,613 belonged in which category w

quire a level of research beyond the scope of this work. The placeme

241,613 in the combat category is, therefore noted. Accordingly, up to 13 

of the total of combat troops could possibly be placed in the logistical 

instead. See “The Organization of the American Expeditionary Forces,” 

Carl Schmidt, “The Operational Slice in Two World Wars,” Military R

(October 1951), 56. 

3. US War Department, Order of Battle of the United States Land F

the World War, American Expeditionary Forces: General Headquarters

Army Corps, Services of Supply, Separate Forces (hereafter Order of Bat

ume 1, 8. 

4. “The Organization of the American Expeditionary Forces,” 14

of Battle, Volume 1, 8; 446-7; US War Department, Order of Battle of th

States Land Forces in the World War, American Expeditionary Forces: D

(hereafter Order of Battle: Divisions), Volume 2, 446-7. The infantry re

headquarters company was so much larger proportionally because it con

signal platoon that provided communications for the entire regiment. See 

Department, United States Army in the World War 1917-1919, Organi

the American Expeditionary Forces, Vol. 1 (Washington, DC: US Army C

Military History, 1988), Table 6, 345. 

5. Ibid.; “The Organization of the American Expeditionary Force

US War Department, Order of Battle, Volume 1, 8; 446-7. 

6. Order of Battle: Divisions, Volume 2, 446-7. 

7. Order of Battle: Divisions, Volume 2, 446-7; John B. Wilson, M

and Firepower: The Evolution of Divisions and Separate Brigades, Ar

eage Series (Washington, DC: US Army Center of Military History, 1998

8. Order of Battle: Divisions, Volume 2, 446-7. 

9. “The Organization of the American Expeditionary Forces,” 142

68-71. The cited division was the 87th. 

10. “The Organization of the American Expeditionary Forces,” 1

son, 53, 67; John McGrath, The Brigade: A History (Fort Leavenworth: 

Studies Institute Press, 2004), 33-4. 

11. This figure includes 13 divisions formed and training in the Unit

as of November 1918. 

56 
Kent R. Greenfield, ed. (Washington, DC: Office of the Chief of Military 

US Army, 1960), 374; Shelby Stanton, Order of Battle, US Army, Worl

(Novato, CA: Presidio, 1984), 4. In terms of motorization, a US infantry 

was roughly the equivalent of a German panzergrenadier (armored infan

sion. While the Germans raised over 200 divisions in World War II, only 

proportion (13) of these were panzergrenadier units. The six excluded 

were five airborne divisions and one mountain division. 

13. Kent R. Greenfield, Robert Palmer, and Bell I. Wiley, The O

tion of Ground Combat Troops, United States Army in World War II: T

Ground Forces (Washington, DC: Department of the Army, 1947), 227. 

14. Greenfield, Palmer and Wiley, 196, 223, 226-7, 297-299. 

15. Robert W. Coakley and Richard M. Leighton, Global Logis

Strategy 1943-1945, The War Department, The US Army in World War I

ington, DC: Office of the Chief of Military History, 1968), 839. 

16. This chart was compiled by looking at a combination of sources 

ing the ETO, particularly the following works: Shelby Stanton, Order o

US Army, World War II, (Novato, CA: Presidio, 1984); US Army, Forc

European Theater, General Board Reports, Bad Nauheim, Germany: 194

2 “Organization of the European Theater of Operations,” and No 127 “O

tion and Functions of the Communications Zone.” 

17. Wilson,180; The 210 headquarters included 83 field artillery 

brigades or corps artillery headquarters, 48 antiaircraft artillery group 

gade headquarters, 13 tank destroyer group headquarters, 83 engineer g

brigade headquarters; Stanton, World War II Order of Battle, 5-6. The 

reorganized were antiaircraft, armor, artillery, field artillery, mechanized 

and combat engineers. Other branches, such as tank destroyers, were alr

ganized on a battalion basis. 

18. US Army, Forces in the European Theater, General Board Repo

Nauheim, Germany: 1945-46, No. 101 “The Employment of Ordnance S

tions, Ordnance Combat Service Units and Ordnance Service Units in t

pean Campaign,” 25, 36, Appendix 15 and 16; US Army, Forces in the E

Theater, General Board Reports, Bad Nauheim, Germany: 1945-46, No 

vice Troop Basis,” 3, Appendix 1 and 2. 

19. Greenfield, Palmer and Wiley, 274-5. 

20. Greenfield, Palmer and Wiley, 320-1. 

21. Roland G. Ruppenthal, Logistical Support of the Armies, Th

States Army in World War II: European Theater of Operations, Volume I

ington, DC: Office of the Chief of Military History, 1959), 304. 

22. Ibid., 310-1, 315, 317, 321, 323, 326-9. 332-4; Matloff, 380. 

23. This, and the following two figures, were compiled from 

tion contained in the following sources: Shelby Stanton, “Korean War 

Battle,” manuscript in the archives of the US Army Center of Military 

Washington, DC; “Statistical Data on Strength and Casualties for Korean 

Vietnam,” Historical Manuscripts Collection (HMC) file 2-3.7 AD.M, U
primary mission was clearly that of life support functions. Some units, t

categorized as logistical may have also actually been committed to life 

functions. 

24. Ibid. 

25. Wilson, 225-7. 

26. Stanton, “Korean War Order of Battle”; “Statistical Data on Stre

Casualties for Korean War and Vietnam.” 

27. Stanton, “Korean War Order of Battle,” Book V, Part XIC, 21-

son, 225-7. 

28. Stanton, “Korean War Order of Battle”; “Statistical Data on Stre

Casualties for Korean War and Vietnam.” 

29. Bob Zelnick, “Soldier Gore: The Story of the Veep and Vietna

tional Review (22 November 1999) [article on-line], available at http://w

articles.com/p/articles/mi_m1282/is_22_51/ai_57436684; Internet; acc

20 March 2007; for 11 to 1, see David Hackworth, “Needed: More Warr

Military Toys,” Defending America, 26 July 1994 [article on-line] ava

http://www.hackworth.com/26jul94.html; Internet; accessed on 20 Marc

30. Ibid. Wilson, 333-6. Since Korea, the Army had reorganized its 

twice, first to the short-lived Pentomic structure in the late 1950s, then in 

1960s to the ROAD organization. ROAD basically applied the World Wa

armored division structure to all divisions, with an increased number o

battalions. The ROAD organization received its baptism of fire in Vietna

31. Shelby Stanton, Vietnam Order of Battle (Washington, DC: U

Books, 1981), 7, 69-230 passim. 

32. Stanton, Vietnam Order of Battle, 1-385 passim. 

33. Wilson, 333, 336-339. 

34. Stanton, “Korean War Order of Battle”; “Statistical Data on Stre

Casualties for Korean War and Vietnam.” 

35. Major Paul Herbert, Deciding What Has to Be Done: General 

E. DePuy and the 1976 Edition of FM 100-5, Operations, Leavenwor

Number 16 (Fort Leavenworth: Combat Studies Institute, 1988), 5-6. 

36. Wilson, 336-7. 

37. Michael J. Meese, “Defense Decision Making under Budget Str

Explaining Downsizing in the United States Army,” (PhD diss., Prince

versity, 2000), 240-242; Major Creighton A., Abrams, Jr. “The Sixteen 

Force: Anatomy of a Decision.” (MMAS thesis, US Army Command and 

Staff College, 1975)`, 27-30. 

38. [US Army] Chief of Staff Memo 74-5-70 for Heads of Army Sta

cies, Subject: Increased Combat Capability in Europe, 2 August 1974, Br

file, Force Structure and Unit History Branch, US Army Center of Mili

tory; “How DoD is Improving the Combat Proportions of U.S. Forces in 

Commander’s Digest 18 (20 November 1975), 2-3; Wilson, 366, 376 

Abrams, Jr., 27-30. 

58 
Troop List, as of 31 March 1974, Part IV, Active Army Troop List, 

13-28, 44-45. This document is found in the archives of the US Army C

Military History. This computation differs from the rationale used by t

Amendment (but not different from that used throughout this work) by 

in the headquarters and support elements of battalion-size units, as well 

larger than battalions. 

40. These programs set up two brigades whose combat troops rotated 

Germany without their dependents for 6-month periods. The rotation con

soon abandoned and the additional brigades, with dependents, were perm

stationed at Wiesbaden and Garlstedt. 

41. Abrams, 15, 19, 26-8. 

42. The differences between the 1968 Vietnam US Army infantry 

and the 1974 US Army armored division are outlined in the following ta

Infantry Division 1968 Armored Division 1974 Difference (ID - A

Number Percent Number Percent Number Pe

Total 16,902 100 15,059 100 -1,843 N

Combat 9,769 58 6,710 45 -3,059 -

Log 1,932 11 3,070 20 +1,138 

HQ 5,201 31 5,279 35 +78 

43. Statistical comparison between the 1943-45 armored division 

1974 armored division: 

Number Percent Number Percent Number Per

Total 10,670 100 15,059 100 +4,369 N

Combat 6,180 58 6,710 45 +530 -1

Log 2,225 21 3,070 20 +845 

HQ 2,265 21 5,279 35 +3,014 +

The comparison between the maneuver battalions of the 1943-45 

division and the 1974 armored division: 

Armored Division 1943-45 Armored Division 1974 Difference 

(AD 43/45 – AD 74) 

Combat No Total Cbt No Total Cbt Bns % Cbt 

Bns Total

Tank 3 2,100 1,335 6 3,120 1,902 +3 +100 +567 

Armored/ 3 2,985 1,401 5 3,830 2,335 +2 +67 +934 

Mech Inf

Total 6 5,085 2,736 11 6,950 4,237 +5 +184 +1,501 

44. George C. Wilson, “Joint Chiefs of Staff Break with Carter on 

Planning,” Washington Post, 30 May 1980, A1. 

45. John Romjue, “A History of Army 86, Volume 1 Division 86: 

velopment of the Heavy Division September 1978-October 1979.” (Fort 
been adjusted to fit the categories used in this work. 

46. John L. Romjue, The Army of Excellence: The Development of t

Army (Fort Monroe, VA: US Army Training and Doctrine Command, 200

204-5. The rough figures were as follows: 

Divisional Elements 17,500 37

Non-Divisional Combat Elements 7,800 16

Non-Divisional Support Elements 22,100 47

Total 47,000 100

47. Romjue, The Army of Excellence, 89. 

48. The standard figure for the ROAD armored division total stren

16,475, while the AOE division strength was 17,104. For ROAD stren

“Active Army Troop List,” 31 March 1974; for AOE strength see Rom

Army of Excellence, 195. 

49. Department of the Army, FM 54-30 Corps Support Groups (Wa

DC: Department of the Army, 1993), 1-4, 1-5,1-8, 1-17; LTC John Va

Forgotten Forces,” Military Review (August 1987), 11. 

50. The figure of 58 percent is slightly skewed. The Army mobiliz

National Guard and Army Reserve units, whose strengths are include

DESERT STORM totals but not in the total size of the Army. In actu

portion of the Active Army strength deployed to Southwest Asia was 

closer to 50 percent of its total strength, a size that meshes with the dep

of 7 out of 14.66 divisions, whose elements all came from the Active A

build up to over 300,000 troops took place in less than 180 days and was 

two consecutive 90-day deployments” XVIII Airborne Corps, August-N

1990 and VII Corps, November 1990-February 1991. 

51. Thomas D. Dinackus, Order of Battle: Allied Ground Forces o

tion Desert Storm (Central Point, OR: Hellgate Press, 2000), 6-7; Vann, 

52. Vann, 2. 

53. The Army had been using the concept of the operational sli

World War II to determine how many troops in the total force were n

field the Army’s basic operational organization. But after Vietnam 

developed an additional conceptual slice—the division force equivalen

The DFE was devised by adding the strength of the division to the nond

forces dedicated to support it in combat. The nondivisional portion of 

was divided into combat and service support increments. While the D

tailored for particular theaters, Army-wide, its service support incremen

the tactical support increment), represented primarily by the corps suppo

had risen to over 20,000. The DFE for armored or mechanized infantry 

projected to deploy to Southwestern Asia (SWA) was 41,000. In 1983, 

was reevaluated as the Army Chief of Staff, General John Wickham, did no

it accurately represented the T3R in the division and its supporting for

Army’s Training and Doctrine Command, therefore, devised a new meth

60 
planning concept was called the operational slice. The table below sh

differences between the two concepts. See Romjue, The Army of Excelle

30, 54, 204-5. The new usage of the expression operational slice referre

a comparison of a predetermined slice of the Army designed to support a 

(including the division itself). In this work, operational slice will still r

comparison of the forces contained in a division versus the total streng

Army. 

a. 

Total 

b. 

Division 

IncrementIncrement 

c. 

Non-Divisional 

Combat 

IncrementIncrement 

d. 

Tactical 

Support 

IncrementIncrement 

e

Divis

PercenPercen

(b/

Division Force Equivalent

41,000 12,900 7,900 20,200 31

Revised as “Operational Slice”

47,400 17,500 7,800 22,100 37

54. US Army Training and Doctrine Command (TRADOC) Pamph

3-90, O & O, The United States Army Objective Force Operational and 

zational Plan for Maneuver Unit of Action, (Fort Monroe, VA: TRADOC

25, 41, 47; Task Force Modularity, US Army Training and Doctrine Co

“Army Comprehensive Guide to Modularity, Version 1.0” (Fort Mon

2004), vi, 5-4. 

55. “Army Comprehensive Guide to Modularity,” 5-5. 

56. Joe Burlas, “Force Stabilization Increases Readiness, Predic

Army News Service, 9 February 2004 [article on-line] available at http:

army.mil/ocpa/read.php?story_id_key=5653; Internet; accessed on 1

2007. 

57. “Army Comprehensive Guide to Modularity,” 8-2; John M

Crossing the Line of Departure: Battle Command on the Move: A Histor

spective (Fort Leavenworth: Combat Studies Institute Press, 2006), 226-

58. Department of the Army, Force Development Division, “Modu

sion 87000G900 Modularity Note 36A,” 8 March 2006, PowerPoint 

“Comprehensive Guide to Army Modularity,” 4-3, 4-4, 5-7, 5-8, 5-9, 5

8-2; McGrath, Crossing the Line of Departure, 226-230. 

59. See note 4, Chapter 1. 

60. BG Yves J. Fontaine and MAJ Donald K. Wols, “Sustai

Momentum: The 1st Corps Support Command in Iraq, Army Logist

(March-April 2006), 3-8; John McGrath, Boots on the Ground: Troop 

in Contingency Operations, Global War on Terrorism Occasional Paper 

Leavenworth: Combat Studies Institute Press, 2006), 135. Some co

were undoubtedly employed in headquarters activities and supporting 
uniformed personnel, such contractors are included in the life support ca

61. Betty Maxfield, “Army Profile FY 05” (Washington, DC: Depar

the Army, Army G1, 2005), 2. Army National Guard (33,177) and Army 

(189,005) strength is not included in these totals even though parts of 

these components were activated in 2005. While several divisions were r

uring into the AOE structure in 2005, the AOE strength is used as all div

Iraq in January 2005 were of the AOE structure. 

62 
NON-DIV/BDE

DIV/BDE

55% 80% 75% 78% 66% 72% 56% 64% 65%

45% 20% 22% 34% 25% 28% 44% 36% 35%

Analysis
 

Overview
 

As mentioned in the Introduction, T3R can be analyzed on two 

by operational slice (operational T3R) and by overall proportion 

tional T3R). The operational slice ratio is significant because it sh

ganizationally what portion of the force the Army organized into 

fighting units. For most of the period between 1917 and 2007, th

unit was the division. Under the modular system, fully impleme

2007, the brigade replaced the division. Figure 42 shows a com

of the operational slices for the Army in the various historical ex

discussed in this work. Thousands

0

10

20

30

40

50

60

70

80

World War I

World War II

Korea

Vietnam

Cold War 1974

Cold War 1976

Div 86 1991

KTO 1991

Army 2005

Modular (2007)

Thousands 

0 

10 

20 

30 

40 

50 

60 

70 

80 

World War I

World War II

Korea

Vietnam

Cold War 1974

Cold War 1976

Div 86 1991

KTO 1991

Army 2005

Modular (2007) 

NON-DIV/BDE 

DIV/BDE 

55% 80% 75% 78% 72% 66% 56% 64% 65%

45% 20% 25% 22% 28% 34% 44% 36% 35% 

Figure 42. Operational T3R Trends, 1917-2005.1 

Division percentages as part of the total force ranged from a 

45 percent in World War I to a low of 20 percent in the McNair/Wo

II era. Divisions, therefore, varied from almost half of the Army 

to a fifth. Since the implementation of the Nunn Amendment in t

1970s, division/brigade proportional strength had risen from the 
AT

more than a third of the force, a ratio maintained by the brigades u

modular Army structure. 

While operational unit proportion gives a good general indic

to the T3R of the Army overall, the operational units themselve

consist entirely of combat elements and some combat elements 

found in divisions or brigades. For example, the World War II ope

slice was so low because AGF Commander Lieutenant General 

McNair organized divisions with minimal organic elements. This 

many combat and support elements, which in other eras were 

parts of the division. 

Accordingly, the overall proportion system, or functional T3R

analyzes deployments unit-by-unit and categorizes them into one 

and three noncombat elements, is a more precise indicator of th

to-tail ratio. Figure 43 gives an overview of the functional T3R 

categories for the case studies examined in this work.2

 Since 191

bat elements have remained between 20 and 50 percent of the tot

Since the mechanized/motorized era (1941), the proportion has re

roughly between 30 and 40 percent, until the mass employment 

tractors in Iraq. A more detailed examination of trends in each c

follows. 

80 

Percent 

60 

40 

20 

0 

COMBAT

TOTAL NONCOMBAT 

World War I

World War II

Korea

Vietnam

Cold War 1974

KTO 1991

Iraq 2005

Iraq 2005 (mod) 

Figure 43. Functional T3R Overview, 1917-2005. 

64 
64%

56%

66%

28% 19% 17%

7.5 7.2% 6.5 

64%

56%

66%

Combat elements progressively declined from over 50 percent 

to 33 percent in Korea, 35 percent in Vietnam and 27 percent 

Cold War Germany. Levels then rose with the adoption of an all-v

Army. Congress intervened to enforce economy and mandate a m

level of combat elements of 29-34 percent. It is uncertain where C

led by Senator Sam Nunn, came up with this figure. But since 191

combat forces in the historical examples examined in this work only 

below the 29 percent figure twice. This occurred once in 1974 whe

enacted his amendment and again in 2005 in Iraq if contractors 

theater base in Kuwait are included in the totals. 

Looking at combat elements in relation to the whole Army 

how small the combat forces actually were in proportion to th

force (Figure 44). The pure combat portion of the Army was as 

6.5 percent in the 1974 Cold War. However, these figures are 

skewed because they only account for the portion of the Army’s 

forces committed to the theaters of war studied in this work. For

Percent30

40

50

World War I

World War II

Vietnam

KTO 1991

20

10

0

%Korea%Cold War 1974

Percent30 

40 

50 

World War I

World War II

Vietnam

KTO 1991 

28% 

20 

19% 17% 

10 

7.2% 

0 

7.5% Korea 6.5% Cold War 1974 

Figure 44. Combat Proportion of the Army, 1917-2005. 
Nunn Amendment

minimal standard

29-34%

and ETO examples. In the case of the AEF, there were essent

inactive theaters. In the ETO example, total strength was reduce

proportional percentage (72) of divisions sent to that theater. W

US Army had worldwide commitments unaccounted for in the 

Vietnam, and Germany case studies, the operations in Kuwait in 1

in Iraq in 2005 were the Army’s main focus, reflecting their highe

Accordingly, the trend has been for raw combat forces to have 

between 10 and 20 percent of the total size of the Army. 

Historical precedent, as depicted in Figure 45, shows that sin

combat elements have only dipped below 30 percent of the total d

force on two occasions. In the first instance, during the immedia

Vietnam period in 1974, Congress immediately noticed and int

to raise the combat level. In the second instance, the modified 20

example, the Army employed a large number of civilian contractor

of the force to conduct noncombat activities. 

60 

Percent 50 

40 

30 

20 

10 

0 

ERA OF MASS MOTORIZATION/ MECHANIZATION 

Nunn Amendment 

minimal standard 

29-34% 

World War I

World War II

Korea

Vietnam

Cold War 1974

KTO 1991

Iraq 2005

Figure 45. Combat Trends, 1917-2005. 

In the modern era of mass motorization and mechanization, w

gan with World War II, the proportion of combat elements has onl

between 40 and 25 percent of the deployed force. The Nunn Ame

66 
(28-34 percent), provided a proportion slightly higher than the com

els in Iraq in 2005. Combat force levels there were already 3 perce

than Nunn’s worst-case proportion, and lower than they have ev

since 1917. The range of combat elements in the modern era (i.e

1941) has been, therefore, between a high of 39 percent, or 1 to 1.

low of 25 percent or 1 to 3.3 

Noncombat Elements 

In terms of range, noncombat elements have been, obviously

verse of the combat elements (Figure 46). Since 1941, they have 

from a low of about 60 percent to a high of 75 percent of the total fo

proportion of noncombat elements since 1917 has progressively in

from under 50 percent to over 70 percent in DESERT STORM. In 

2005, military logistical forces declined by 10 percent from 1991

extensive use of civilian contractors in support roles formerly ma

soldiers accounts primarily for this decline. By including contrac

support elements in Kuwait in the totals, noncombat elements ro

percent, levels exceeding those of pre-Nunn Amendment German

noncombat element is examined separately in the following sectio

Percent

40

45

50

55

60

65

70

75

80

World War I

World War II

Korea

Vietnam

Cold War 1974

KTO 1991

Iraq 2005

Percent 

40 

45 

50 

55 

60 

65 

70 

75 

80 

World War I

World War II

Korea

Vietnam

Cold War 1974

KTO 1991

Iraq 2005

Figure 46. Noncombat Trends, 1917-2005. 
Extensive Use

of Civilian

Contractors

CAL &

Extensive

Use of Host

Nation

Support

LO AL 

Civilian

Contractors

included in

total

Logistical and life support elements together rose from under 

cent to about 45 percent of the total force after World War I, with 

velopment of mass Army mechanization and motorization. Togeth

two elements hovered in the range between 45 and 47 percent. Th

tween one-third and one-half of the force, for the rest of the period 

(Figure 47). Fluctuations in the size of logistical elements undo

reflects factors such as host nation support in Germany and in Iraq 

where civilian contractors assumed responsibility for many logisti

life support) functions. To approximately account for these factors, 

that the higher range (40-45 percent) of the historical size of logist

ments, including life support, which will be discussed separately b

a good guideline for a minimum proportional figure. In support of t

postwar study presented a figure of 44 percent as the appropriate 

logistical support for a division from all theater assets.4 

60 

55 

50 

45 

40 

35 

30 

25 

20 

Civilian 

Contractors 

AL 

included in 

total 

LOGISTIC

LIFE SUPP

LOGISTI

LIFE SUPPORT

CAL &

ORT 

Extensive 

Use of Host Extensive Use 

Nation 

Support 

of Civilian 

Contractors 

World War I

World War II

Korea

Vietnam

Cold War 1974

KTO 1991

Iraq 2005

Figure 47. Logistical Trends, 1917-2005. 

68 
 

growth of logistical support requirements. These requirements in

markedly during the course of the 20th century and on into the 2

largely to advancements in weapons technology. Weapons beca

gressively larger, more complex and more mobile, theoretically re

a larger number of logistical troops to support them. The M1 t

instance, required three times the fuel of its predecessor, the M

between 1970 and 1991, the necessary minimum stockage level fo

ment repair and spare parts increased by 20 percent (or one-fi fth 

However, logistical elements only rose about 5 percent proportiona

ing this period.5 

Logistical elements were surprisingly one area where the Arm

chose to economize, particularly in the 1970s and in later force de

tiatives. This led some logisticians to fear that logistical elements h

proportionally reduced to a dangerous level. However, trends in Ir

the extensive use of host nation support and civilian contractors, 

have mitigated these fears as the logistical proportion of the force 

levels not seen since World War II.6 

Since motorization in 1941, logistical elements (including l

port) ranged between 36 and 57 percent of the total force or betwee

half to three-fourths of all noncombat elements. The variation se

pendent on the availability of host nation support and civilian con

The higher figure of 57 percent does, in fact, include civilian con

Overall, including contractors, logistical elements have seen a ste

crease, particularly since 1974. 

The Rise of Headquarters 

The proliferation of headquarters is a long-recognized feature 

ern armies. Such headquarters have not just expanded to comm

control combat elements, but have also risen to manage noncom

ments. A good example of this was the creation of the materiel m

ment center in ROAD divisions in the 1970s, an agency respons

managing the assets and functions of divisional and nondivisional 

cal units. In this work, the headquarters elements of all units, b

and above, have been taken into account, no matter what type of 

primary mission the unit had. In the early 1970s, Congress was th

define headquarters elements, even those controlling combat uni

tions, as rightfully belonging to the tail rather than the tooth in t

Congress, however, unlike this work, did not include headquart

ments at battalion level as part of this equation. 
War I to a height of almost 40 percent in the 1974 Cold War period 

many. Since 1974, via various organizational restructurings, the 

tion of headquarters elements has progressively declined to a lev

percent in Iraq in 2005 (Figure 48). Since motorization in 1941, th

of proportional size of headquarters varied between 16 and 38 

Surprisingly, considering the apparent proliferation of headquarte

ganizational changes since 1974, there may have been more head

(such as aviation and engineer brigade headquarters in AOE div

but these headquarters were overall smaller in size than when the

fewer, but larger headquarters in Korea, Vietnam and pre-1976 C

Germany. Percent

0

10

20

30

40

50

Percent 

0 

10 

20 

30 

40 

50 

World War I

World War II

Korea

Vietnam

Cold War 1974

KTO 1991

Iraq 2005

Figure 48. Headquarters Trends, 1917-2005. 

Life Support Functions 

The last noncombat category is life support. Expeditionary ope

particularly extended expeditionary operations, require a certain pro

of the deployed force be employed in infrastructure and other 

missions, which, while not directly supporting combat operations, 

MWR and base camp support of various types. In a theater wher

70 
between the rotations by providing preexisting camps and services 

49). 

Figure 49. Life Support Trends, 1917-2005. 

Percent

0

2

4

6

8

10

12

14

16

World War I

World War II

Korea

Vietnam

Cold War 1974

KTO 1991

Iraq 2005

Percent 

0 

2 

4 

6 

8 

10 

12 

14 

16 

World War I

World War II

Korea

Vietnam

Cold War 1974

KTO 1991

Iraq 2005

Although generally removed from direct combat, life suppo

tions can have an indirect effect on the combat element of a force, 

For example, in the Iraqi deployment in 2005 two combat brigad

virtually permanently devoted to guarding major installations and t

support activities. In recent deployments, civilian contractors have 

an increased role in life support functions. Since traditionally such 

nel are not soldiers, they need someone to protect them whenever 

doing their functions. This study considers such contractors, exce

conducting logistical missions, to be part of the life support eleme

Units performing primary missions of life support are often 

to determine from looking at orders of battle or other documentary 

als. Accordingly, as highlighted in the logistical elements section 

chapter, life support functions have often been consolidated with 

cal ones. In several case studies, (Korea, Vietnam, Iraq), examina
COMBAT

LOGISTICAL

HEADQUARTERS

AVERAGES SINCE 19

54 COMBAT

22 LOGISTICAL

24 HEADQUARTE

COMBAT

LOGISTICAL

HEADQUARTERS

AVERAGES SINCE 19

54 COMBAT

22 LOGISTICAL

24 HEADQUARTE

cases, life support functions varied between 6 percent and 14 perce

ure 47). 

The Functional T3R within Operational Units 

The previous discussion of operational units (divisions, brig

this chapter stressed their relationship to the Army as a whole. H

the internal composition of these organizations also contained bo

bat and noncombat elements. The preceding chapter discussed this 

functional T3R in each presented historical example. Figure 50 

rizes the proportional figures from these case studies. Average perc

for the post-1918 era were 54 percent for combat elements, 22 per

logistical components and 24 percent for the headquarters portion

Percent

0

10

20

30

40

50

60

70

80

AEF Division 1918

Inf Div 1945

Arm Div 1945

Inf Div 1953

Lt Inf Div 1968

Arm Div 1974Arm Div 1986

Stryker Bde 2004

Modular CA Bde 2007

Percent 

0 

10 

20 

30 

40 

50 

60 

70 

80 

AEF Division 1918

Inf Div 1945

Arm Div 1945

Inf Div 1953

Lt Inf Div 1968

Arm Div 1974Arm Div 1986

Stryker Bde 2004

Modular CA Bde 2007 

COMBAT 

LOGISTICAL 

HEADQUARTERS 

AVERAGES SINCE 19

54 COMBAT

22 LOGISTICAL

24 HEADQUARTE

Figure 50. Operational Unit Functional T3R, 1917-2005. 

The post-1918 functional T3R average for combat elements of 

cent, or slightly more than half of the soldiers in divisions and b

were 21.5 percent higher than similar figures throughout the force 

ater. In the latter cases, combat forces were about a third of the f

the same time, Army or theater-wide, noncombat elements forme

72 
formed less than half. Among the noncombat elements, headquar

ments were approximately the same size in operational units as ove

versus 27 percent). But the average strength of the logistics eleme

more than 20 percent lower (22 versus 47.5 percent combined life 

and logistical proportion). Combat elements had been, therefore, in

primarily at the expense of logistical elements in division/brigade

Summary 

Since 1917, the US Army’s functional tooth-to-tail ra

progressively risen in favor of noncombat elements until 197

Congressionally mandated T3R of that year temporarily slowed th

However, by 2005, noncombat elements had risen proportionally t

fourths of the force size, primarily because of the mass employ

civilian contractors in Iraq in the new millennium. Each of the ca

(combat, logistical, headquarters and life support) has shown an 

range of values since 1941 as indicated in Table 9. 

Table 9. Range of Functional T3R Percentages by Category7 

a. b. c. 

Highest Lowest Average A

Percent Percent A

Combat 39 25 32.5 

Total (76) (60) 74.5 

Noncombat

Logistical8 43 32 37.5 

Headquarters 38 16 27 

Life Support 14 6 10 

Column c is the average figure of the high and low values. 

d adjusts these figures to a sum of 100 percent, using the average 

figure as an unchanging baseline (see note 7). The figures in co

provide a snapshot of what the noncombat factors would be based 

torical average when the combat element is at its historical avera

is useful because it provides the mean percentage or mean functio

found in the US Army from 1945 to the present. 

This work has provided a quick look at the tooth-to-tail rat

1917. The biggest shift in the functional T3R ratio was between 

War I and World War II. Reflecting the effects of mass motorizat
39 percent. While a drop of 14 percent is not as great as the pos

War I range (15 percent—see Table 9) of combat values, never do 

figures rise higher than 40 percent again. This provides a range or 

combat and noncombat values. Using average figures, combat forc

been about a quarter of the force, while logistics elements were ro

third of the force or half of the noncombat elements. On an averag

quarters elements composed a quarter of the force (or slightly mor

third of all combat elements). Units or contractors providing life 

functions formed less than 10 percent of the total force and slight

than a tenth of all noncombat elements. 

While combat elements averaged 32.5 percent and ranged betw

and 25 percent since 1941, recent trends in combat forces are w

toward the lower end of the range, rather than the higher end or e

average. When civilian contractors are included, combat elements, 

exception of a Congressionally mandated increase in the mid-197

progressively declined since 1945. This, and other issues, are disc

the next chapter. 

74 
1. The data used to make this graphic is found in Table B-3. 

2. The column marked, “Iraq 2005 (mod),” on this and subseque

refer to the Iraqi deployment in January 2005, including contractors and 

Kuwait. 

3. In this calculation, the 40 percent figure for Iraq excluding co

and the Kuwait base is not used as the high figure because when modif

these additions, it is reduced to 25 percent. Similarly, the 42 percent for 

1953 without the Japan base is also not used because it too, upon modifi

reduced, in this case, to 33 percent. 

4. LTC Harry Page and LTC Lawrence Fuller, “Use of ‘Operation

Factors,” Military Review 28 (January 1949), 42. 

5. Vann, 10-11. 

6. Ibid. 

7. The noncombat figures in this column are adjusted proportiona

der to attain a total percentage of 100. Unadjusted, the percentage is 107 

In order to attain 100 percent, the average combat figure of 32.5 is reta

baseline. The noncombat elements, accordingly, need to be reduced toget

their sum of 74.5 to 67.5 percent. This adjustment factor is 0.906402 (67

In other words, the noncombat factors in column c are multiplied by th

to produce the figures in column d, which represent 91 percent of the av

column c. 

8. Life support elements are not included in this figure as they we

sectional discussion. 

Conclusions
 

General Conclusions
 

As highlighted in the last chapter, combat elements have progr

declined as a proportion of the total force since 1945. This trend 

cussed in detail in the next section of this chapter. Apart from the 

of combat forces, there are several other general conclusions tha

drawn based on the historical study of the tooth-to-tail ratio. 

The Impact of Mass Motorization Caused the Largest Sh

T3R 

While in general terms, the creation of the AEF marked the 

of the modern US Army, particularly in organizational terms, a

the functional T3R. The level of noncombat elements was far lo

percent) than it has ever been since then. While logistical troops 

over a third of the force (39 percent), headquarters were tiny (9 p

far smaller than the modern (post-1941) range of 16-38 percen

the Army expanded and reorganized to fight World War II in 1940

Army Ground Forces introduced motorization and mechanization 

the board. Ironically, this transformation affected logistics the le

gistical/life support elements rose only 6 percent (39 to 45) to 1

an average increase of 8.5 percent (47.5) in the period since 1941

same time, headquarters doubled in size, proportionally, betwee

and 1945 (8 to 16 percent) and continued to rise after World War 

an average increase of 19 percent (37.5). 

The T3R in Vietnam Was Not Abnormal 

The paucity of combat elements in Vietnam has been cited pub

often, and usually without attribution, that to many military observ

low proportion of combat troops in that conflict has become ax

However, an analysis of the US Army order of battle in South V

after the Tet Offensive in 1968 reveals that combat troops actually 

a third (33 percent) of the force deployed in country. This total w

ally slightly higher than the combat troop average (32.5 percen

1945. While life support elements were slightly higher than the po

average (13 versus 10 percent), the logistical component was actu

percent lower than that average (30 versus 37.5). In terms of the fu

tooth-to-tail ratio, Vietnam was well within the range of postwar 

tions. The ratio of combat versus noncombat elements was 1 to 2. 
Expected from Observing US Army Reorganizations sinc

Almost every US Army reorganization since the beginning o

War II has entailed the expansion of headquarters elements. Gene

ley McNair’s pooling created a number of separate battalions, ea

headquarters elements roughly equivalent to the size and role of r

tal headquarters prior to 1941. McNair also created numerous grou

quarters to control separate battalions. Later reorganizations added 

cal, aviation, engineer and artillery headquarters, both to the divis

nondivisional forces. This expansion reached a height of 38 perce

Army in Cold War Germany in 1974. But the major lasting effec

Nunn Amendment was, perhaps at least in spirit, a trend in head

reduction. After 1974, headquarters proportional size progressiv

clined, first to 28 percent in the 1991 Gulf War, then to 18 percen

in 2005. The latter figure was only 2 percent higher than that of t

Army (18 versus 16 percent). 

Life Support Elements Are Hard to Differentiate 

In all modern expeditionary operations, the presence of life sup

ements is apparent in the infrastructure of camps and their intrinsic 

elements. However, interpreting which units are primarily conduc

support operations, as opposed to logistical support operations, is 

to discern from orders of battle. Accordingly, in this work, these 

ments often had to be merged. In the 2005 Iraq deployment, a larg

ber (28,000) of civilian contractors performed life support operati

The Logistical Component Continues to Rise 

While this point may seem obvious, in the 1980s, some senior 

commented on fears that the Army or the Department of Defense 

duced logistics elements to dangerously low levels.1 These fears 

unfounded. While logistical/life support elements did decline t

of 35 percent in Germany in 1974, deployments in Saudi Arabia 

(42 percent) and in Iraq and Kuwait (57 percent), where large num

troops were dispatched to areas without previous US-style infrast

the logistical/life support elements rose to their highest levels eve

1991, there has been a great expansion in the use of civilian con

most of whom are employed in logistical or life support functions

Divisions and Brigades Contain a Higher Combat Functi

T3R than the Army as a Whole 

As shown in Figure 50 (page 72), the functional T3R for Arm

sions (1945-2005) and brigades (2004-07) averages 54 percent in 

78 
the Army as a whole during the same period (32.5 percent). The 

in combat elements was reflected in similar reductions in the non

components of the division/brigade. Accordingly, the logistical por

eraged 15.5 percent less than that of the Army overall (22 versus 3

headquarters troops composed 3 percent less of these organizations 

the entire Army (24 versus 27). 

In terms of trends rather than averages, divisional and brigade 

elements have remained higher than the Army-wide average in rece

ganizations, but to a lesser extent. The 1986 armored division ma

a proportion of 49 percent combat elements, while the Stryker brig

percent) was slightly higher and the modular combined arms briga

less (43 percent). In the noncombat portion, while overall this po

the division remains smaller proportionally than the Army as a wh

logistical element in divisions and brigades has risen almost to 

Army-wide.2 This segment was 20 percent in the 1974 Armored D

26 percent in the Division 86 armored division and 30 and 33 

respectively, in the Stryker brigade and in the 2007 modular Co

Arms Brigade. The latter figure in particular is only 4 percent low

the Army-wide average (33 versus 37.5). 

At the Operational Level, a Third of the Army is Found i

Units Designed to Fight the Enemy 

Since 1917, the US Army employed basic operational units, d

and brigades (the latter under the modular system adopted Army-

2007). These units comprised between 45 and 20 percent of the tot

with an average proportion of 32.5 percent. Accordingly, through

20th century and on into the 21st century, a third of all soldiers we

nized into operational units. While at the tactical level, these units w

composed solely of combat troops, and many combat elements we

divisions, from the perspective of the Army as a whole, these divisi

brigades were roughly equivalent to the combat elements at lowe

Accordingly, it is interesting that the historical average of operatio

proportion, 32.5, exactly equals the historical average of combat e

in the functional T3R (32.5—see Table 9). 

Trends and Ranges 

Trends 

Based on the analysis in the previous chapter, it is possibl

vise average fi gures for each functional T3R category based on h

examples since 1941. Table 9 depicted these averages. Figure 5

Table 9 onto a pie chart.3 
34% 

32.5% 

24.5% 

Combat

Logistics

HQ/Admin

Life Suppo

Combat 

Logistics 

HQ/Admin 

Life Suppo

9% 

Figure 51. Functional T3R Averages, 1945-2007. 

While useful to give an overview of proportional ratios, aver

not tell the whole story. The averages give a mean figure over a p

time (since 1945), but trends may have certain categories incre

declining above or below the average figure. For example, whil

quarters elements averaged 24.5 percent, in the most recent depl

Iraq 2005, the headquarters portion was only 18 percent. The in

also true. While logistics elements averaged 34 percent, in Saud

in 1991 (42 percent) and in Iraq in 2005 (57 percent) the proport

much higher. 

Combat elements reflect this as well. They have consistently d

since 1945 (Figure 52). The average figure of 32.5 primarily reflec

bat levels before 1974. Since then, combat elements have fallen 

and further below the 32.5 average percent. In 1974, Congress m

a minimum combat level of between 29 and 34 percent of the tot

deployed in Germany. The resulting increase in combat levels re

below the average level. After 1991, combat elements further dec

proportional size, falling 7.5 percent below the average figure an

cent below Congress’ 1974 minimum figure. 

Even though in Iraq and Kuwait in 2005 the combat proportion 

to 25 percent, this level is a historical low, 7.5 percent below th

since 1941 and a 5 percent decrease since 1991. It was also 4 

below the Nunn Amendment’s recommended proportion (29-34 p

80 
Percent 36 

38 

Nunn Amendmen

minimal standard 

29-34 % 

34 

32 

30 

28 

22 

24 

26 

Average Combat 

Proportion since 

1941 (32.5 %) 

20 

World War II

Korea

Vietnam

Cold War 1974

KTO 1991

Figure 52. Combat Trends Since 1941. 

However, in terms of trends, it continues the proportional do

movement in combat percentage. 

Figure 53 illustrates the trendlines for combat and noncombat e

over time since World War II. The trend for combat forces has 

decline roughly 2.16 percent over time in the next campaign/depl

with noncombat elements increasing by a similar percentage. 

Such trends are abstract mathematical concepts applied to 

history. There are many factors involved in future operations, suc

nature of the operation, weapons and equipment, and technology

will affect whether combat elements will continue to decline a

percent rate in future operations, or remain the same or even inc

proportional size. 

Ranges

Despite their steady decline, the importance of the combat e

cannot be overemphasized. All the other categories primarily sup

activities of the combat portion, either directly or indirectly. Acco

a comparison between functional T3Rs at both ends of the 
Figure 53. Functional T3R Trendlines. 

proportional range provides insight into the size of the noncombat e

and their fractional relationship to the combat portion. Figure 54 il

the proportions using the minimum (Iraq 2005) and maximum (ET

combat figures in the motorization era to illustrate the extreme end

combat spectrum as illustrated in the examples used in this work

maximum value, logistical and life support elements are combine

on the availability of data from the ETO deployment. Percent 

80 

70 

60 

50 

40 

30 

20 World War II

Percent

20

22

24

26

28

30

32

34

36

38

Percent 

20 

22 

24 

26 

28 

30 

32 

34 

36 

38 

World War II

Korea

Cold War 1974

KTO 1991

TOTAL NON-COMBAT 

LOGISTICAL & 

LIFE SUPPORT 

HEADQUARTERS 

Korea

Vietnam

Vietnam

Cold War 1974

KTO 1991

Iraq 2005 Iraq 2005 (w/contractors (w/contractors & K uwait) & K uwait) 

82 
Figure 54. Maximum and Minimum Functional T3R Levels. 

18% 

25% 

43% 

Combat

Logistics

HQ/Admin

Life Support

Combat 

Logistics 

HQ/Admin 

Life Support 

13% 

16% 

39% 

45% 

COMBAT COMBAT 

IRAQ 2005 ETO 1

Logistical & 

Life Support 

Combined 

56% 

In these examples, the variations between the minimum and m

values give the ranges for each category (Table 10). While both com

logistical/life support ranges varied by more than 10 percent, head

values remained within a range of 2 percent in both the minim

maximum examples. This would tend to indicate that within the fu

T3R framework, headquarters elements can be expected to form 

17 percent of the force under most conditions, despite a general 

increase by 3.3 percent. 

Table 10. Range of Functional T3R Percentages Based on 

Minimum and Maximum Combat Percentages 

a. b. 

Maximum Minimum 

Combat Combat V

Combat 39 25 

Total 61 75 

Noncombat

Logistical & 45 56 

Life Support

Headquarters 16 18 
As mentioned, this study is a companion volume to a previou

Boots on the Ground, which looked at the number of troops (or tro

sity) required to successfully conduct contingency operations. W

study estimated a proportion of 13.26 troops per 1,000 of civilian 

tion, it did not detail the composition of the 13.26. In general ter

work fills that void. Although Boots only addressed contingency 

tions and this work looks at major deployments of all types, militar

employed in contingency operations are always general purpos

rather than specialized troops. The forces studied in this volume w

general purpose troops. Accordingly, T3R ranges and trends de

from the study of such operations may also be applicable to cont

operations. Figure 55 places the minimum and maximum percent p

from Figure 54 into the numerical context of the 13.26 troop level

T3R 

13.26 BY 

CATEGORY 

MAXIMUM 

COMBAT 

POLICE 

AND OTHER 

DUTIES 

9.16% 

MINIMUM 

COMBAT 

13.26 PER 

THOUSAND 5.17 

2.12 

5.97 

4.10 

2.12 

5.51 1.53 

Logistical & 

Life Support 

Combined 

7.04 

TROOP DENSITY 

POLICE 

TYPE 

DUTIES 

4.1 

Combat 

LogisticsLogistics 

HQ/Admin 

Life Suppo

Figure 55. T3R and Troop Density.5 

Boots on the Ground postulated, based on the force levels 

temporary urban police departments, that in a contingency oper

minimum of 4.1 soldiers per thousand of population were recom

to be devoted to the conduct of police-type (i.e., combat) operatio

84 
While the combat number in the maximum example exceeds thi

(5.17), the proportional total in the minimum sample (13.26 x 25% 

was below the figure by 0.74. In Figure 55, the combat figure wa

to the minimum of 4.1 and the noncombat categories were acco

decreased by the same amount (see note 4). 

The fact that the unadjusted combat proportion figure in the m

combat sample (3.3) was below the minimum prescribed in Boot

Ground (4.1) is interesting because the minimum combat sample re

the deployment in Iraq in January 2005. Accordingly, the num

combat troops in that operation was 0.74 less soldiers/police per th

of population. This seemingly slight difference actually represents 

5.5 percent of the suggested figure of 13.26 total troops per thou

population. Pending the outcome of operations in Iraq, future p

need to look at and analyze the significance of this minor variance 

composition. 

Summary 

This work examined the major US Army overseas deploymen

World War I and analyzed them in terms of the tooth-to-tail ratio—

portion of combat troops to noncombat troops—at two levels: th

tional T3R (proportion of divisions and brigades in the whole Arm

at the tactical level, the functional T3R, which divided Army units 

egories by function and determined the proportions. Interestingly 

the average historical proportion of combat forces for both the op

al and functional T3Rs were the same: 32.5 percent of the tota

With regard to the functional T3R, since the advent of motoriz

the start of World War II, the T3R has only varied 14 percent in t

proportional change between combat and noncombat elements. H

in this 14 percent, trends show a steady general decline in comba

of about 2 percent per operation during the period studied. While t

Nunn Amendment temporarily prescribed a minimum proportional 

level of 29 percent, recent trends in combat size have been as low as 

cent. While headquarters elements expanded throughout the peri

showed a variance of only 2 percent between the minimum and m

historical examples, showing, perhaps, a trend of leveling off in th

Applying T3R proportions to troop density proportional size 

tions presented in Boots on the Ground reveal that combat elemen

in Iraq in 2005 may have been slightly (5 percent) below the recom

ed level if troops in the Kuwait base and civilian contractors are i

in the overall figure. 
at a relatively steady rate. This trend measures roughly a 2.16 per

cline per each subsequent campaign. There are many possible rea

this decline. Perhaps the nature of warfare and technology has cha

the extent that lesser combat troops are needed. The large-scale in

tion of civilian contractors into expeditionary warfare in the rec

deployment is the most significant of such changes. Increased 

ogy, primarily in the form of digital communications, provides, p

higher levels of command and control and situational awareness, a

for decreased combat forces. Perhaps different types of operations 

lower levels of combat troops or more specialized forces. How

the percentage of combat troops deployed declines, it raises the q

of whether such a deployment is, in fact, a military deploymen

or some other type of operation not requiring military forces, or 

not the general purpose forces traditionally used in most overseas 

ments. 

Whatever the reason for the trend of declining combat el

future force designers need to be aware that combat troops have 

a range between a quarter and slightly over a third of all general 

forces deployed by the United States since World War II. They al

to be aware that, within this range, the historical trend is that t

recent deployments have had the smallest proportions of combat e

and the oldest deployments the highest levels. While the trend sh

overall decline in the combat portion, force planners need to rea

any force levels following the 2.16 percent trend of decline would 

producing an unprecedented low level of proportional combat el

At some point, there will be a level of diminishing returns where 

purpose forces deployed overseas will have too few combat tr

successfully complete military missions. 

Perhaps the lowest threshold for combat force proportion h

reached or is close to being reached. With only a quarter of its fo

voted to combat activities, the deployment in Iraq has lasted over 

And even this size estimate may be an overestimate. The employ

contractors and other elements less able to defend themselves 

result in combat elements protecting these elements. For example

in 2005, two combat brigades were devoted specifically to theater 

roles. These brigades primarily defended large logistics bases a

vided security for convoys between the large bases. 

In 1974, Congress passed the Nunn Amendment, specifi cally p

ing a tooth-to-tail ratio for US forces in Germany. The legislators 

86 
combat troops. While combat elements have decreased over time at 

rate, the Nunn standard has only been violated in the Iraqi deploym

percent). The nature of warfare or the unique circumstances involv

particular deployment may call for a reduced employment of com

ments. On the other hand, this line has only been crossed once, ma

Iraq 2005 level a unique occurrence. Whether this is a true cont

of trends since 1945 or a special situation is a debatable point. A th

study of the Iraq deployment is necessary to determine whether t

bat troop level is adequate or a case of diminishing returns. 

In almost every previous expeditionary operation, the Unite

has employed general purpose forces. These are forces designed 

duct military operations across the spectrum of intensity and again

ous threats. Planners need to consider this in the development of 

portional level of combat elements in such a force. While the force 

tailored for nation building, peacekeeping and counterinsurgency

eral purpose force is still primarily a fighting element. Otherwise, 

would not be given this mission in the fi rst place. 

This work provides a brief quantitative look at the tooth-to-t

in US forces in major deployments and operations since 1917. As 

illustrates trends, ranges and averages based on force levels of t

While expeditionary warfare is often changing and situationally 

dent, as force designers plan for the future, the past illustrates T3

es and trends previously considered to be effective. Deviations f

historical record should only be made with caution based on com

reasons. 
1. For examples of these comments, see Vann, 2-3. 

2. While the AOE armored division contained 51 percent of no

elements, the ratio Army-wide in 1991 was 70 percent. In Iraq in 2005, w

noncombat proportion was 75 percent, AOE divisions (51 percent) and 

Brigades (48 percent) were still considerably smaller proportionally. 

3. This figure displays the average combat figure and the noncom

ures reduced by a factor of 0.9, adjusted to fit a 32.3 combat percentage. 

4. John J. McGrath, Boots on the Ground: Troop Density in Con

Operations, Global War on Terrorism Occasional Paper 16 (Fort Leav

US Army Combat Studies Institute, 2006), 109. 

5. The minimum T3R figures on this chart require some explanat

original proportion combat figure was 3.36 (25 percent of 13.26). How

accordance with Boots on the Ground, a minimum of 4.1 troops out of t

need to be devoted to police/combat duties as a minimum (see McGrat

on the Ground, 106).Therefore the 3.36 figure has been raised to 4.1, an 

of 0.74. Accordingly, the three noncombat categories have to be reduce

0.74 or 0.246 each. These adjustments are reflected in the minimum pie c

table below shows these shifts: 

Category 

a. 

Percentage 

b. 

Number 

(13.26 x a/100) 

c. 

Adjustment 

Factor 

d. 

Adjust

Figur

Combat 25.32 3.36 +0.74 4.10

(b + c

Logistical 43.34 5.75 -0.25 5.51

(b – c

Headquarters 17.89 2.37 -0.25 2.12

(b – c

Life Support 13.45 1.78 -0.25 1.53

(b – c

Note: Fractions were rounded off. 

6. McGrath, Boots on the Ground, 79,106. In the context of con

operations (peacekeeping, counterinsurgency, occupation duties), police

ties are considered to be synonymous with combat functions. In fact, in th

military police units operating in Iraq, in January 2005 were counted a

elements. 

88 
 

 

 

 

 

 

 

 

 

 

 

 

 

AAA antiaircraft artillery 

AD Armored Division 

ADA Air Defense Artillery 

AEF American Expeditionary Force 

AGF Army Ground Forces 

AOE Army of Excellence 

ARVN Army of the Republic of Vietnam 

BCT brigade combat team 

BDE Brigade 

BN Battalion 

BTB brigade troops battalion 

CA Combined Arms 

CBT Combat 

COMZ Communications Zone 

CP command post 

CSB Corps Support Battalion 

CSG Corps Support Group 

DFE Division Force Equivalent 

DISCOM Division Support Command 

DIV Division 

EECP Early Entry Command Post 

ETO European Theater of Operations 

HHC Headquarters and Headquarters Company 

HQ headquarters 

ID Infantry Division 

KTO Kuwaiti Theater of Operations 

ID Infantry Division 

KW Korean War 

MCG Mobile Command Group 

MECH mechanized 

MI Military Intelligence 

MLRS Multiple Rocket Launcher System 

MP Military Police 

MWR Morale, Welfare and Recreation 

NATO North Atlantic Treaty Organization 

NBC Nuclear, Biological, Chemical 

ROAD Reorganization Objective Army Division 

RSTA Reconnaissance, Surveillance, and Target Acquisition 

SHAEF Supreme Command Allied Expeditionary Force 

SOF Special Operations Forces 

SWA Southwestern Asia 

T3R Tooth-to-Tail Ratio 

TAC Tactical Command Post 
TD Tank Destroyer 

TOE Table of Organization and Equipment 

TRADOC Training and Doctrine Command 

US United States 

XO executive officer 

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98 
T3R Categories
 

Table A-1. Categories of the Tooth and the Tail

Combat Noncombat Noncombat 

HeadquarHeadquarters &

Administrative 

LogisticalLogistical Life Support

Mission Units whose primary mission is

the conduct of combat and

combat support operationsperations.

Units or elements of units which

provide command and control

for combat, combat support and

combat service support units;

units which provide support to

headquarheadquarters units.

Conduct service support

operations (CSS), including

internal combat service support

operations in CSS units.

Conduct infrastructure support.

Types

Of Units

• Company/troop/batteroop/battery/

detachments of infantry,

armor, cavalry, field artillery,

air defense artillery, combat

engineerengineers.

• Special operations forces

units of all sizes.

• Advisors and other elements

directly supportingupporting the

combat forces of foreign

armies.

• Attack and assault aviation

units of company or smaller

size.

• Military police units providing

convoy protection.

• Headquarters battalions/

companies/troops/batteries/

detachments of all types of

command from battalion to

theater headquartersquarters

(including logistical units).

• Most signal units.

• Most military intelligence

units.

• Command and control

aviation units.

• Military police units tasked

with command and control

functions (traffic control),

headquarheadquarters guard.

• Command public information

units.

• Most combat service support

units (quarter(quartermaster, supply,

service, maintenance,

ordnance, adjutant general,general,

transportation,ortation, medical, small

finance).

• Internal logistical elements in

combat battalions.

• Internal logistical elements in

logistical units.

• Combat service support

aviation units (air ambulance,

heavy lift, etc.).

• Military police units running

POW camps, etc.

• Civil affairs units.

• Base support units.

• Signal infrastructure units.

• Construction and infrastructure engineer units.

• Military police units running

prisons for friendly forces,

etc.

• Larger finance units.

• J AG offices.

• Labor service support units.

• Headquarters units for units

conducting life support

functions.

• Base public information

(adjutant general) units.

• Contracting units. 

Comparative Data Tables
 

Table B-1. Operational Unit (Division/Brigade) Composition Comp

Table B-2. Theater Comparisons by Category*
 

Table B-3. Operational Slice Comparisons*
 

Table B-4. Overall Combat Forces Proportion*
 

Table B-5. Historical Data
 

*The data in these tables were produced through an analysis of vario

of battle and troop list documents found in official histories and station

To determine categories for units above company level, tables of organiz

the specific units were examined. 
102
 

Table B-1. Operational Unit (Division/Brigade) Composition Comparisons

Unit Type 

Division/

Brigade

Size1 

Combat Noncombat

LogisticalLogistical HeadquarHeadquarters &

Administrative

Number % Number % Number %

AEF Infantry Division, 1918 28,105 22.040 78 4,048 14 2,017 7

Infantry Division ETO, 1945 14,037 9,544 68 1,911 14 2,572 18

Armored Division ETO, 1945 10,670 6,180 58 2,225 21 2,265 21

Infantry Division Korea, 1953 20.036 12,345 62 3,610 18 4,081 20

ROAD Infantry Division Vietnam, 1968 16,092 9,769 58 1,932 11 5,201 31

ROAD Infantry Division Germany, 1974 15,059 6,710 45 3,070 20 5,279 35

AOE Armored Division, 1968 17,003 8,403 49 4,300 26 4,300 25

Stryker Brigade, 2004 4,798 2,515 52 1,443 30 840 18

NotionalNotional Modular Heavy Division, 2004 22,177 8,586 39 6,394 29 7,197 32
Table B-2. Theater Comparisons by Category 

Theater 

Combat Noncombat

LogisticalLogistical Life Support HeadquarHeadquarters and

Administrative 

Number % Number % Number % Number %

AEF, 1918 1,866,1841,866,184 984,116 53 782,262 39 153,805 8

ETO, 1945 2,156,7392,156,739 828,402 39 979,017 45 349,320 16

Korea/Japan, 1953 354,819 115,581 33 131,651 37 21,452 6 86,135 24

Vietnam, 1968 324,030 113,820 35 75,120 23 39,571 12 96,801 30

Germany, 1974 186,719 51,170 27 65,094 35 70,455 38

KTO, 1991 332,565 99,781 30 139,239 42 94,545 28

Iraq, 2005 135,000 53,768 40 48,705 33 32,527 24
Table B-3. Operational Slice Comparison

a.

Area or

Element Element 

b.

Total

Strength 

c.

Number of

Divisions/

Brigades Brigades 

d.

Standard

Divisional/

Brigade Brigade Size 

e.

Total

Operational

Slice

(b/c) 

f.

Division/

Brigade

Percentage

of the Army

(d/e) 

g.

NonDivisional/

Brigade Brigade Slice

(e-d) 

h.

NonDivisional

Percentage

of the Army

(g/e) 

Army, 1918 2,395,742 43 28,105 55,715 50 27,610 50

AEF, 1918 1,866,184 32 28,105 58,318 48 34,100 55

Army (World

War II) 1945

6,042,277 89 13,800 67,900 20 54,100 80

Army (Korean

War) 1953

1,533,815 20 18,804 76,691 25 57,887 75

Army (Vietnam

War) 1968

1,570,343 21 16,475 74,778 22 58,303 78

Army, 1974 783,330 13.5 16,475 58,204 28 41,549 72

Army, 1976 779,417 16 16,475 48,714 34 32,239 66

Army, 1991 572,423 14.66 17,104 39,046 44 21,945 56

Kuwaiti Theater

of Operations,

1991

333,565 7 17,104 47,652 36 30,548 64

ModularBrigade, 2007

500,000 48 3,735 10,477 36 6,682 64

104
 
Table B-4. Overall Combat Forces Proportion1

World War I

1918 

World War II

(ETO) 

Korea

1953 

Vietnam

1968 

Cold War

1974

Germany 

KTO

1991 

Iraq

2005 

Total Army

Strength

3,514,137 4,308,1142 1,533,615 1,570,343 783,330 572,423 468,578

Combat 984,116 828,402 115,581 113,820 51,170 99,781 52,768

Percent 28 19 7.5 7.2 6.5 17 11

 Robert R. Palmer 1. , “The Mobilization of the Ground Army,” Army Ground Forces Study Number 4 (Washington, DC: Army Ground Force

1946).

This 2. figure represents 72 percent of the Army’s 1945 strength (the proportion of the Army in the ETO). 
NA

Table B-5. Historical Data 

106
 a. Area or

Element Element 

b.

Total

Strength 

c.

Combat

Elements Elements 

d.

Total

Noncombat

Elements Elements 

e.

Logistical

Elements 

f.

Headquarters

Elements 

g.

Life

Support

Elements 

AEF, 1918 1,866,184 984,116 282,068 128,262 153,806 *

AEF Division, 1918 28,105 21,620 6,485 4,048 2,437 NA

ETO, 1945 2,167,409 834,582 1,332,827 981,242 351,585 *

Infantry Division,

1945

14,037 9,554 4,483 2,572 1,911 NA

Armored Division,

1945

10,670 6,180 4,460 2,225 2,265 NA

Army Korea

(including Japan)

354,660 115,419 239,241 131,654 86,135 21,452

Korea Infantry

Division, 1953

20,036 12,345 7,691 3,610 4,081 NA

Army Vietnam, 1968 305,156 100,553 204,603 72,694 92,338 39,571

Vietnam Infantry

Division, 1968

16,902 9,769 7,133 1,932 5,201 NA

USAEUR Germany,

1974

186,822 51,170 135,549 57,626 70,455 7,468

Armored Division,

1974

15,059 6,710 135,549 57,626 70,455

Armored Division,

1986

17,104 8,403 8,701 4,446 4,255 NA

Army-DESERTSTORM, 1991

333,565 99,781 23,784 139,239 94,545 *

Army Iraq (including

Kuwait) 2005

223,000 56,456 166,540 96,641 39,903 29,996

Stryker Brigade

4

798 2

515 2

283 1

443 840 NA
capacity or another since 1978. A retired Army Reserve officer, Mr. McG

in infantry, field artillery and logistics units, both on active duty and a

Before coming to work at the Combat Studies Institute, he worked fo

the US Army Center of Military History in Washington, DC, as a h

archivist. Prior to that, Mr. McGrath worked full time for the United 

Reserve in Massachusetts for over 15 years, both as an active duty r

as a civilian military technician. He also served as a mobilized reservi

Saudi Arabia with the 22d Support Command during Operation DESE

as the command historian and in 1992 at the US Army Center of Mili

as a researcher/writer. Mr. McGrath is a graduate of Boston College a

MA in history from the University of Massachusetts at Boston. He i

of numerous articles and military history publications and the follow

Theater Logistics in the Gulf War, published by the Army Materiel C

1994; The Brigade: A History, published by the US Army Combat Stud

in 2005; Crossing the Line of Departure: Battle Command on the Mov

on the Ground: Troop Density in Contingency Operations, both publ

US Army Combat Studies Institute in 2006. Mr. McGrath was also 

editor of the proceedings of the Combat Study Institute’s 2005 Mili

Symposium, An Army at War: Change in the Midst of Conflict and co

CSI’s anthology In Contact! Aside from a general interest in things 

historical, his areas of particular interest include modern military ope

German Army in World War II, August 1914, and the Union Army 

War. He also has a keen interest in ancient history, historical linguist

of Boston, and baseball. McGrath is also a current PhD candidate at K

University. 

The Long War Series
 

Occasional Paper 23
 

Combat Studies Institute Press
 

Fort Leavenworth, Kansas