Combined Action Program The Combined Action Program was a United States Marine Corps operational initiative implemented in the Vietnam War and proved to be one of the most effective counterinsurgency tools developed during that conflict . Operating from 1965 to 1971 , this program was characterized by the placement of a thirteen - member Marine rifle squad , augmented by a U . S . Navy Corpsman and strengthened by a Vietnamese militia platoon of older youth and elderly men , in or adjacent to a rural Vietnamese hamlet . In most cases , the Popular Forces miltia members ( Nghia Quan ) were residents of the hamlet who were either too young or too old to be drafted into the Army of the Republic of Viet Nam ( ARVN ) or the Regional Forces ( Dia Phuong Quan ) . The entire unit of American Marines and Popular Forces militia members together was designated as a Combined Action Platoon ( CAP ) . The program was said to have originated as a solution to one Marine infantry battalion ' s problem of an expanding Tactical Area of Responsibility ( TAOR ) . The concept of combining a squad of Marines with local ( PFs ) and assigning them a village to protect proved to be a force multiplier . While the exact implementation varied with the stage of the war and local command variations , the basic model was to combine a Marine squad with local forces to form a village defense platoon . It was effective in denying the enemy a sanctuary at the local village level . The pacification campaign seemed to work under the CAP concept , and the Marines fully embraced it . Objectively , there is no solid proof that the CAP concept was a resounding success ; however , subjectively the evidence suggests otherwise . " Counterinsurgency operations and , in particular , the establishment of a foreign internal defense lends itself for the greatest utility of employing a CAP - style organization . Recent operations in Somalia , Haiti , and Bosnia suggest a CAP - style organization could accomplish the assigned mission . " In Iraq , the Marines reinstituted a variant of the CAP US Marine background for combined programs . The CAP concept seems to have been at least partially based on Marine pacification programs in Haiti , Nicaragua , the Dominican Republic , and elsewhere , during the Banana Wars in the late 19th and early 20th centuries . In these programs , Marine units would pacify and administer regions , while providing training and security for local forces and villages . There are also connections to other pacification programs , such as the Philippine Insurrection . " CAP came naturally for the Marine Corps because counterguerrilla warfare was already part of the USMC heritage . From 1915 to 1934 , the Corps had a wealth of experience in foreign interventions fighting guerrillas in Nicaragua , Haiti , and Santo Domingo . For example , the Marines organized and trained the Gendarmerie d ' Haiti and the Nacional Dominicana in Haiti and Santo Domingo from 1915 to 1934 . In Nicaragua ( 1926 – 1933 ) , the Marines organized , trained , and commanded the Guardia Nacional de Nicaragua . These organizations were nonpartisan , native constabularies the Marines commanded until host - nation forces could competently assume command . " " The historical background of Army and Marine counter - insurgency operations , the perceived enemy center of gravity in Vietnam , the strategic aim , and identified critical enemy factors are key to understanding Marine versus Army operational differences on conducting the " Other War . " It was these differences and past Marine experience that contributed to the creation of the U . S . Marines ' Combined Action Platoon ( CAP ) . Initial Motivation and Organization . Opinions differ about exactly how and where Combined Action originated , but it seems to have started in August 1965 as a unit drawn from 3rd Battalion , 4th Marines , under LtCol William W . Taylor in the Phu Bai ( 3 / 4 ) area . 3 / 4 ’ s TAOR included six villages and an airfield in a ten square mile area . The unit was overextended , and Taylor ' s executive officer , suggested that they incorporate local militia units into 3 / 4 ' s operations . Taylor sent the plan to COL E . B . Wheeler , Commanding Officer ( CO ) of the 4th Marine Regiment , who forwarded it to the III Marine Amphibious Force ( IIIMAF ) and Fleet Marine Forces Pacific ( FMFPAC ) . Major General Lew Walt and Lieutenant General Victor Krulak , both of whom had fought in the Banana War , saw the potential value and agreed to the proposal . GEN Nguyen Van Chuan , the local Army of the Republic of Vietnam ( ARVN ) CO , gave Walt control of the Vietnamese platoons near Phu Bai . Taylor integrated four squads with the local PF units in August 1965 . 1stLt Paul Ek was designated as unit commander . ( Ek had some training in Vietnamese and counterinsurgency operations . ) The Marines were handpicked volunteers from 3 / 4 , carefully screened by the executive officer , Maj Zimmerman . " Zimmerman drew upon his knowledge of the British Army ' s experiences in 19th Century India . While studying British procedures of that era , Zimmerman had developed an appreciation for the British propensity towards " Brigading . " He knew that by combining a British unit with one or more native units , the British were not only able to increase the size of their army for a comparatively small investment of British troops , but also succeeded in increasing the quality of the native units . This was in Zimmerman ' s mind when he developed the plan that called for combining a U . S . Marine rifle squad with a PF platoon to form an integrated self - defense force that was able to protect the village from low level Viet Cong threats . The combining of the Marines and the PFs was seen as optimal since both brought unique qualities to the union . The PFs , a poorly trained and often neglected home guard , brought knowledge of people and terrain . They also brought the emotional benefits associated with defending their homes . The Marines brought the benefits of highly trained , well led , aggressive combat troops . MG Walt formalized the program in February 1967 , appointing LTC William R . Corson as the III MAF deputy director for Combined Action . Corson believed CAP should have a separate chain of command , as it was his opinion that the average battalion commander in Vietnam often didn ’ t know or care how to succeed in combined action , since they were trained and oriented toward offensive large - unit warfare . Corson saw CAP as being mobile and offensive in nature , a concept which later took shape in the mobile CAP units . However , Corson eventually became disenchanted with the conduct of the war In spite of this rocky start , CAP became an official " hearts and minds " civic action program , and a school of sorts was eventually established near Da Nang . Training was brief ( ten days ) and covered a few bare essentials – some Vietnamese phrases , customs , and culture , some civic action precepts , and some military topics – far too short to be of much real good , though a step in the right direction . Upon graduation , you were posted to your unit . Eventually they began issuing certificates showing you had graduated . Initially , CAP Marines were issued a special cloth and leather insignia to be worn from the button on the breast pocket of the uniform jacket . These were later replaced by handsome enameled metal pins , also made to be worn on the breast pocket . These , however , were easily lost , and also made a good aiming point for the enemy . They were usually dispensed with on patrols . The CAP concept in Vietnam was opposed by some who considered " hearts and minds " programs a waste of money , men , and materiel . CAPs were often ignored at best and despised at worst by many area commands and commanders . The prevailing concept was ; " Get ' em by the balls and their hearts and minds will follow . " This attitude made the CAP Marines ' job that much more difficult . However , the concept eventually gained backing from Marine generals Wallace Greene , Victor Krulak and Lew Walt , and with their support , the program expanded . By 1969 , despite losses during the 1968 Tet Offensive , the program had expanded to 102 platoons comprising 19 companies and 4 groups , and was even mentioned by President Lyndon B . Johnson in a speech . . CAPs peaked in 1970 , with 4 Groups , and 114 companies , spread through the 5 provinces of I Corps . Organization . While they were not as highly trained for working with host nation personnel as United States Army Special Forces , in 1965 the US Marine Corps Combined Action Program ( CAP ) took on a role of reinforcing and training local village soldiers , although their basic missions differed substantially . ( See Comparison with Non - Marine Programs below for details ) This small program had a number of phases . At its inception it was unofficial and did not have a standard organization . Some units were called " Joint Action Companies " ( JACs ) . Since , in US military jargon , the word " joint " refers to something pertaining to a combination of forces from different services , and " combined " references a combination of forces from more than one nation , they were , at first , renamed CACs , for " Combined Action Companies . " CAC was changed to CAP , for " Combined Action Platoons " . From a purely military standpoint , the units were of platoon , not company , strength . In addition , " cac " is a Vietnamese word for the male generative organ , and the motto included the phrase " suc manh " , which means strength . The implications were naturally humorous to the Vietnamese . In the last phase of development , when Marines were no longer permanently assigned to individual villages , the program was renamed to CUPP , for the " Combined Unit Pacification Program . " CAP has remained the most common name . Initial structure . To work with the PFs , III MAF instituted the combined action platoon ( CAP ) , consisting of a 13 - man Marine rifle squad ( if you were fortunate enough to have 13 ) augmented by a U . S . Navy Corpsman and paired with a 15 - to 30 - man PF platoon to defend one particular village . Each element of the team strengthened the other . The Marines contributed firepower , training , and access to American medical evacuation and artillery and air support CAP units consisted of a Marine rifle squad with a US Navy Medical Corpsman , teamed with a Vietnamese Popular Forces platoon ( The PF was roughly equivalent to the US National Guard , but with less training and poorer equipment ) . CAPs were generally commanded by a Marine sergeant , but were sometimes commanded by corporal s . Patrols were often led by lance - corporals . In some cases such as CAP 1 - 4 - 1 in 1969 they were commanded by Lance Corporals . Combined Action Platoons were frequently semi - isolated and usually independent units . Headquarters CAPs were sometimes “ double ” CAPs – i . e . ; two CAP squads , one comprising the HQ personnel , the other the patrol and defense element . They were eventually organized as platoons , which in turn formed companies , which were organized into Combined Action Groups ( CAGs ) . Eventually there were four CAGs in I Corps . Originally , the units lived in or near the villages they were affiliated with , eventually in a fortified area . Individual units were assigned to villages in an ostensibly “ pacified ” area , usually one to a village , though they might serve several other villages in the area . Initially , they were identified by letters and numbers , like line units . Later , numeric designators were used . Reorganization , 1966 – 67 . According to the Command Chronology of HQ 3rd Marine Division ( Reinforced ) dated 10 November 1966 ( provided by Larry Larsen , formerly of Sub Unit # 5 ) ; “ Combined Action Company ( in northern I Corps ) joined our rolls as Sub Unit # 4 , an administrative division of HQ 3rd Marine Division ( Reinforced ) . Later , they operated under Sub Unit # 5 , then returned briefly to SU # 4 . ” The CC ’ s “ Narrative Summary ” for December 1966 mentions various branches supporting CACs Alpha ( Houng Thuy ) , Hotel ( Phu Loc ) , and a fourth portion of HQ 3rd MarDiv ( Rein ) deployed to Khe Sanh in support of the Senior Officer Present . In southern I Corps , the CAC units that were part of Task Force X - ray , a brigade command of the 1st Marine Division , were placed under the administrative control of the 7th Communications Battalion when the Chu Lai TAOR was turned over to the U . S . Army in April , 1967 . Each CAP was operationally supported by the nearest American battalion , whether Marine Corps or U . S . Army . In October , 1967 , the Combined Action Program underwent a major reorganization with the creation of the 1st Combined Action Group in Chu Lai under Lt . Col . Day , the 2nd Combined Action Group in DaNang and the 3rd Combined Action Group in Phu Bai . All three CAG headquarters reported directly to III MAF . In February 1967 , the Narrative Summary notes the establishment of Sub Unit # 5 at Khe Sanh . ( That corresponds roughly to the establishment of Oscar Company , then operating under SU # 5 . ) The report mentions building CAP sites , patrols , and other events , but generally doesn ’ t break them down by company or platoon . I have only found references to Alpha , Hotel , and Papa as separate entities . On 15 July 1967 , the CC notes that SU # 4 was assigned TAD to III MAF , and on 29 July 1967 that the CAC personnel of SU # 5 were reassigned to SU # 4 . In October 1967 , the CC notes that “ the 3rd Combined Action Group ( CAG ) was activated as a separate unit under III MAF ( operating out of Phu Bai ) effective 1 October 1967 . The remaining 1 officer and 16 enlisted in SU # 4 continued to function as CAG members until normal attrition reduced them to zero effective 30 November 1967 . Roving CAP of 1968 . " Beginning in about 1968 , the CAP concept underwent some changes . Due to factors such as a high number of attacks and casualties among the static CAPS , the " roving CAP " was started . Roving CAPs had no fixed village – they rotated among two or more villages , and often spent the night in the field . They were very mobile , as opposed to the original static concept , and thus kept the enemy guessing as to where they would be any given night . " Although CAPs sacrificed a degree of control in the villages , the Marines proceeded with the Mobile CAP concept and by 1970 all CAPs were converted . According to the III MAF staff letter , the justification for this conversion included the facts that ; the links with the PFs were still intact ; it avoided the " mole " mentality of a static position ; it denied the enemy information as to the exact location of the unit , thus , reducing casualties ; it allowed the Marines to make better use of supporting arms by being outside the populated areas ; and allowed the Marines to concentrate their strength by not requiring the unit to guard a base . CAPs were also redesignated beginning about the same time . They went from alpha - numeric designations , ( such as Oscar - 2 ) , to numeric designations , such as 2 - 7 - 4 . The first digit designated the group ( 1 – 4 ) , the second designated the unit ( replacing the letters ) , and the third designated the platoon . 1970 reduction . At the beginning of 1970 , Marine strength in the Combined Action Program had reached its peak . Four CAGs were in operation : In January 1970 , the four CAGs consisted of a total of 42 Marine officers and 2 , 050 enlisted men , with two naval officers and 126 hospital corpsmen . Organized in 20 CACOs and 114 CAPs , these Americans worked with about 3 , 000 RF and PF soldiers . The 2d CAG in Quang Nam , largest of the four , consisted of eight CACOs with 36 CAPs and almost 700 Marine and Navy officers and men , while the smallest , the 4th in Quang Tri , had three CACOs and 18 CAPs With the US participation in the war drawing down , III MAF reduced the CAP platoons as it redeployed its regular forces . On 21 September 1970 , the Marines officially deactivated CAP as a separate command within III MAF . In its 5 years of operation , CAPs operated in more than 800 hamlets , containing approximately 500 , 000 Vietnamese civilians in I Corps . Comparison with Non - Marine Programs . CAP was one of several programs , during the Vietnam War , where US personnel worked as a team with a local defense group . " The Marines and the U . S . Military Assistance Command , Vietnam , disagreed on war strategies . U . S . Army leaders [ other than Special Forces ] wanted to search and destroy the communists in the rural and less - populated areas of South Vietnam ; the Marines wanted to clear and hold the populated areas . CAP was a manifestation of the strategy the Marines felt best suited the conditions in Vietnam . " With U . S . Marines living and fighting side - by - side with the Vietnamese people , CAP seemed to represent an effective , long - term , around - the - clock commitment to combating the Vietnamese communists at the grassroots level . CAP worked well in some locations ; elsewhere , its results were transitory at best — with villagers becoming over - reliant on the Marines for security . " There were some similarities between what CAP did and what was done by the United States Army Special Forces ( aka Green Berets ) . However , most Marine units worked in the lower lying areas with Vietnamese RF / PF units , while Special Forces tended to work in more remote areas using a variety of troops , including indigenous minorities such as the Sino - Vietnamese Nung and Dega ( aka " Montagnard " ) tribesmen . ( An exception to this pattern was Oscar Company , which was stationed at Khe Sanh in the mountainous regions of Quang Tri . The Marines drew from the same local Dega tribe , the Bru , as the Special Forces of nearby FOB 3 , though the Special Forces , since they could offer a better rate of pay , usually got their pick of the tribe . ) The main difference between the Marine CAP and the Army programs was that the Marine program was a " hearts and minds " civic action program seeking to gain the trust and friendship of the Vietnamese they lived and worked with through a combination of military training and civic action projects , while the Special Forces Civilian Irregular Defense Group ( CIDG ) combined village defense units with mobile strike forces of mercenary light infantry . The original CIDG programs with Special Forces were sponsored by the Central Intelligence Agency , and were essentially a mercenary unit program . However , most of the CIDG units eventually became Army of the Republic of Vietnam ( ARVN ) Ranger units . An additional combined operation involved MACV - SOG Military Assistance Command Vietnam Studies and Observations Group . ( Studies and Observations Group was actually a code for Special Operations Group . ) These were not local defense , but highly secret covert cross - border operations ( aka " black ops " ) , in areas the US was not officially operating in at that point in the war , such as Laos , Cambodia , and North Vietnam . In many cases , both units formed a strong bond with their indigenous counterparts – a necessity for small units operating alone deep in enemy - held terrain . Eventually , the regular Army also initiated a form of CAP – US Army Civil Action Patrol Team – similar to the Marine CAP on a smaller scale . However , they didn ' t live in the villages as the Marines did . Typically they were a 3 - man team including an officer , enlisted instructor and radiotelephone operator . The HQ was in a nominally secure area , and they ventured out to arranged meeting places to provide instructional support in weapons maintenance , etc . One such element was an adjunct of the 1st / 502d Inf , 101st Airborne Division and was sited at Eagle Beach in June 1970 . ( The foregoing per former Army CAPT member , " M - 60 " Mike Kelley , in an E - mail to F . J . Taylor , USMC ( Ret . ) , formerly of CAP Oscar - 2 . Unfortunately , the original E is no longer extant . ) Effectiveness . " Of all our innovations in Vietnam none was as successful , as lasting in effect , or as useful for the future as the Combined Action Program [ CAP ] . " Combined Action was at least in some areas a successful program in both military and civic action terms – perhaps one of the few successful programs of that war . Relatively cheap to operate , CAPs seldom used costly supporting arms fire , had a high " kill " ratio relative to the size of the unit . According to LTC James H . Champion , USMC ( Ret . ) ; " In April and May 1969 , 1st CAG killed 440 VC or NVA , and 1st CAG was killing more NVA than the entire 101st Airborne Division . 1st CAG had about 400 Marines and sailors at the time . Elsewhere in his article he states : “ From 1966 until 30 June 1969 they { CAP NCOs } lead small units which killed over 4400 VC / NVA . ” They were often popular in the villages they worked in , and succeeded in denying them to the VC . " Of the 209 villages protected by CAP units , not one ever reverted to VC control . Of all the data compiled , subjective or objective , this one undeniable achievement remains as an example of success unparalleled in the war . Just by their presence CAP units were able to establish RVN primacy and served as one fact that VC propaganda could not explain away . CAP Marines are often fondly remembered and have been well received by their former villages when they re - visited Vietnam . Indeed , some have gone back there to work , doing much the same civic action that won their friendship originally . Harold P . Ford , who held senior positions in both the National Intelligence Council and the Directorate of Operations , offers some insights on Secretary of Defense Robert McNamara ' s evaluation of the situation in Vietnam ; " The large - unit operations war , which we know best how to fight and where we have had our successes , is largely irrelevant to pacification as long as we do not have it . Success in pacification depends on the interrelated functions of providing physical security , destroying the VC apparatus , motivating the people to cooperate and establishing responsive local government GEN William C . Westmoreland , commanding general , Military Assistance Command Vietnam was not an advocate of pacification programs . He believed in large unit land warfare , and was trying to stage a full - scale land battle with the NVA that would ostensibly break them for once and all . Nonetheless , he wrote in his memoirs that the Combined Action Program was one of the more " ingenious innovations developed in South Vietnam According to Peter Brush , " Civic action had promise . Had it been adopted on a wide scale the war would have been different , but it is a matter of speculation as to whether it would have ultimately affected the outcome . " Other writers including MAJ Edward Palm , who was once a CAP Marine , thought otherwise . " I would like to believe , with some , that combined action was the best thing we did . . . . . . In my experience , combined action was merely one more untenable article of faith . The truth , I suspect , is that where it seemed to work , combined action wasn ' t really needed , and where it was , combined action could never work . " . Tom Flynn CAC Papa3 Marine . A Voice of Hope , 184p . p . ISBN # 1 - 56167 - 133 - 9 , References . American Literary Press , 1994 . Also see copies found in Marine Corps Historical Center , Building 58 , Washington Navy Yard , 901 M Street , S . E . , Washington , DC 20374 5040