i

The United States Army War College

U.S. ARMY WAR COLLEGE

CENTER for

STRATEGIC

LEADERSHIP and

DEVELOPMENT

The United States Army War College educates and develops leaders for service 

at the strategic level while advancing knowledge in the global application 

of Landpower.

The purpose of the United States Army War College is to produce graduates 

who are skilled critical thinkers and complex problem solvers. Concurrently, 

it is our duty to the U.S. Army to also act as a “think factory” for commanders 

and civilian leaders at the strategic level worldwide and routinely engage 

in discourse and debate concerning the role of ground forces in achieving 

national security objectives.

The Strategic Studies Institute publishes national 

security and strategic research and analysis to influence 

policy debate and bridge the gap between military 

and academia.

The Center for Strategic Leadership and Development 

contributes to the education of world class senior 

leaders, develops expert knowledge, and provides 

solutions to strategic Army issues affecting the national 

security community.

The Peacekeeping and Stability Operations Institute 

provides subject matter expertise, technical review, 

and writing expertise to agencies that develop stability 

operations concepts and doctrines.

The Senior Leader Development and Resiliency program 

supports the United States Army War College’s lines of 

effort to educate strategic leaders and provide well-being 

education and support by developing self-awareness 

through leader feedback and leader resiliency.

The School of Strategic Landpower develops strategic 

leaders by providing a strong foundation of wisdom 

grounded in mastery of the profession of arms, and 

by serving as a crucible for educating future leaders in 

the analysis, evaluation, and refinement of professional 

expertise in war, strategy, operations, national security, 

resource management, and responsible command.

The U.S. Army Heritage and Education Center acquires, 

conserves, and exhibits historical materials for use 

to support the U.S. Army, educate an international 

audience, and honor Soldiers—past and present.

U.S. Army War College

Senior Leader Development and Resiliency

SLDR

STRATEGIC

STUDIES

INSTITUTE

The Strategic Studies Institute (SSI) is part of the U.S. Army War 

College and is the strategic-level study agent for issues related 

to national security and military strategy with emphasis on 

geostrategic analysis.

The mission of SSI is to use independent analysis to conduct 

strategic studies that develop policy recommendations on:

• Strategy, planning, and policy for joint and combined 

 employment of military forces;

• Regional strategic appraisals;

• The nature of land warfare;

• Matters affecting the Army’s future;

• The concepts, philosophy, and theory of strategy; and,

• Other issues of importance to the leadership of the Army.

Studies produced by civilian and military analysts concern 

topics having strategic implications for the Army, the Department of 

Defense, and the larger national security community.

In addition to its studies, SSI publishes special reports on topics 

of special or immediate interest. These include edited proceedings 

of conferences and topically oriented roundtables, expanded trip 

reports, and quick-reaction responses to senior Army leaders.

The Institute provides a valuable analytical capability within the 

Army to address strategic and other issues in support of Army 

participation in national security policy formulation.

iii

v

Strategic Studies Institute

and

U.S. Army War College Press

THE ETHICS OF DRONE STRIKES:

DOES REDUCING THE COST OF CONFLICT 

ENCOURAGE WAR?

James Igoe Walsh 

and

Marcus Schulzke 

September 2015

The views expressed in this report are those of the authors and 

do not necessarily reflect the official policy or position of the 

Department of the Army, the Department of Defense, or the U.S. 

Government. Authors of Strategic Studies Institute (SSI) and 

U.S. Army War College (USAWC) Press publications enjoy full 

academic freedom, provided they do not disclose classified 

information, jeopardize operations security, or misrepresent 

official U.S. policy. Such academic freedom empowers them to 

offer new and sometimes controversial perspectives in the interest of furthering debate on key issues. This report is cleared for 

public release; distribution is unlimited.

*****

This publication is subject to Title 17, United States Code, 

Sections 101 and 105. It is in the public domain and may not be 

copyrighted.
vi

*****

Comments pertaining to this report are invited and should 

be forwarded to: Director, Strategic Studies Institute and U.S. 

Army War College Press, U.S. Army War College, 47 Ashburn 

Drive, Carlisle, PA 17013-5010. 

*****

This manuscript was funded by the U.S. Army War 

College External Research Associates Program. Information on 

this program is available on our website, www.StrategicStudies

Institute.army.mil, at the Opportunities tab.

*****

All Strategic Studies Institute (SSI) and U.S. Army War 

College (USAWC) Press publications may be downloaded free 

of charge from the SSI website. Hard copies of this report may 

also be obtained free of charge while supplies last by placing 

an order on the SSI website. SSI publications may be quoted 

or reprinted in part or in full with permission and appropriate 

credit given to the U.S. Army Strategic Studies Institute and U.S. 

Army War College Press, U.S. Army War College, Carlisle, PA. 

Contact SSI by visiting our website at the following address: 

www.StrategicStudiesInstitute.army.mil.

*****

The Strategic Studies Institute and U.S. Army War 

College Press publishes a monthly email newsletter to update 

the national security community on the research of our analysts,

recent and forthcoming publications, and upcoming conferences sponsored by the Institute. Each newsletter also provides 

a strategic commentary by one of our research analysts. If you 

are interested in receiving this newsletter, please subscribe on the 

SSI website at www.StrategicStudiesInstitute.army.mil/newsletter.

ISBN 1-58487-700-6
vii

FOREWORD

Armed unmanned aerial vehicles—combat 

drones—have fundamentally altered the ways the 

United States conducts military operations aimed 

at countering insurgent and terrorist organizations. 

Drone technology is on track to becoming an increasingly important part of the country’s arsenal, 

as numerous unmanned systems are in development and will likely enter service in the future. The 

increasingly frequent use of drones raises profound 

questions about the nature and morality of warfare 

involving asymmetrical risks between opposing belligerents. Concerned citizens, academics, journalists, 

nongovernmental organizations, and policymakers 

have raised questions about the ethical consequences 

of drones and issued calls for their military use to be 

strictly regulated. This level of concern is evidence 

that the future of drone warfare not only hinges on 

technical innovations, but also on careful analysis of 

the moral and political dimensions of war. Regardless 

of whether drones are effective weapons, it would be 

difficult to sanction their use if they undermine the 

legitimacy of U.S. military forces or compromise the 

foundations of democratic government. 

One key ethical challenge drones raise is that removing American soldiers from the battlefield could 

alter civilians’ attitudes toward the use of military 

force in ways that promote war and undermine democratic accountability. Casualty aversion, the civilian 

public’s discomfort with sustaining military casualties 

and resistance to costly military operations, is a powerful constraint on when and how wars are waged in 

democratic societies. Political leaders in such polities, 

and even some high-ranking commanders within the 
military, may feel pressured by public opinion to wage 

wars in ways that minimize the risk to soldiers, or to 

avoid fighting entirely when casualties are likely. One 

of the most popular and plausible arguments against 

the use of drones is that these weapons subvert the 

constraints created by casualty aversion in potentially 

dangerous ways. Drones may allow wars to be waged 

without risk to human soldiers and therefore without 

the risk of provoking public backlash. The weakening 

of this constraint might permit leaders to initiate or escalate conflicts that, absent the availability of drones, 

might generate domestic political controversy. In what 

follows, Dr. Marcus Schulzke and Dr. James Walsh 

discuss the logic of such arguments against drones, 

and touch upon counterarguments which suggest that 

drones might permit war to be waged in a more ethical manner than current weapons technologies permit. 

Although the argument that drones will subvert 

casualty aversion is one of the most common objections raised against these weapons, it has not been 

subjected to much systematic empirical investigation. 

It is generally substantiated with inferences drawn 

from past wars and with theoretical accounts of how 

drones may promote civic disengagement. The authors assess this argument with a survey experiment. 

Participants were randomly assigned to read information about fictional conflict scenarios. These scenarios 

varied the type of attack by U.S. forces, describing it as 

drone strikes, strikes from manned aircraft, or the use 

of ground troops. They also systematically altered the 

strategic goals of the military mission, which included 

counterterrorism, humanitarian intervention, the restraint of an aggressive foreign power, and support 

for an ally facing an internal military threat to its hold 

on power.

viii
ix

Their results show that participants are more willing to support the use of force when it involves drone 

strikes. Support for attacks increases noticeably when 

it is described as a drone strike. However, this technology’s influence on support for military interventions may not be as profound as critics of drone warfare often argue. Indeed, one important shortcoming 

of philosophical and ethical reflections on the effects 

of drones is that they do not produce very precise 

estimates about how sizable a change in opinion the 

introduction of this technology will create. An important contribution, then, is to compare how drones alter 

opinions compared to other factors known from existing research that alter support for the use of force.

For example, gender has an influence on support 

for war that was comparable to using drones. Existing research suggests that gender has a consistent, but 

not overwhelming, large effect on attitudes towards 

military force. While one should use care in generalizing from the results of one experiment, these findings 

suggest that the possibility of engaging in military action with drones should, in general, increase support 

for the use of force by a modest amount. The practical 

consequences of such changes would depend on how 

closely the public was divided on a proposed military 

mission. 

Many factors are at play when leaders propose to 

or actually use force. The availability of combat drones 

may be one such factor, but that alone is unlikely to 

be decisive in most scenarios. It also indicates that the 

type of military action matters. Participants were more 

likely to support wars that posed lower levels of risk 

to American soldiers, but they were also more likely 

to support wars in pursuit of important objectives (es-
pecially for counterterrorism) and when they thought 

that war was generally an effective foreign policy tool. 

This suggests that critics of drones are correct in calling attention to the risk of drones lowering inhibitions 

against war, but that this shift in attitudes alone is unlikely to have a strong effect on the incidence of wars.

 

 DOUGLAS C. LOVELACE, JR.

 Director

 Strategic Studies Institute and

 U.S. Army War College Press

x
xi

ABOUT THE AUTHORS

MARCUS SCHULZKE is a Post-Doctoral Research 

Fellow in the School of Politics and International Studies at the University of Leeds, West Yorkshire, England. He has published research on the morality of 

drone warfare, moral decisionmaking in combat, and 

just war theory for such journals as Political Studies, 

The Journal of Military Ethics, and Philosophy and Technology. Dr. Schulzke holds a Ph.D. in political science 

from the University at Albany, NY, with a dissertation 

on how soldiers make ethical decisions during counterinsurgency operations. 

JAMES IGOE WALSH is Professor of Political Science 

at the University of North Carolina at Charlotte, NC. 

His research interests include the military and political consequences of advanced weapons, links between 

natural resources and conflict, and intelligence and 

national security. His work has been supported by the 

Army Corps of Engineers, the Department of Homeland Security, the National Science Foundation, and 

the Minerva Research Initiative. Dr. Walsh is the author of The International Politics of Intelligence Sharing, 

published by Columbia University Press, New York, 

and was named an Outstanding Title by Choice. Dr. 

Walsh holds a Ph.D. in international relations from 

American University. 

xiii

SUMMARY

One of the most compelling arguments that has 

been raised against drone weapons is that they may 

lower inhibitions against going to war by making it 

possible to fight without sustaining casualties. This 

monograph assesses this argument by using a survey experiment designed to gauge whether American civilians are more willing to initiate wars using 

unmanned aerial vehicles (UAVs) than using ground 

forces or piloted aircraft. The use of UAVs made participants more likely to support initiating a war, and 

this was consistent across four principal policy objectives that were the cause for war: counterterrorism, 

humanitarian intervention, foreign policy restraint, 

and internal political change. However, the increase 

in support for war caused by UAVs was fairly small, 

and would probably not be sufficient to tip the balance of public opinion in favor of fighting under most 

circumstances. Support for war was also heavily influenced by other factors, such as what principal policy 

objective was being pursued.

1

THE ETHICS OF DRONE STRIKES:

DOES REDUCING THE COST OF CONFLICT 

ENCOURAGE WAR?

INTRODUCTION AND OVERVIEW

Drones have had a revolutionary influence on 

U.S. military operations over the past 2 decades. This 

technology is on track to become an increasingly important part of the country’s arsenal as the dozens of 

unmanned systems currently in development enter 

service in the future. Drones have also raised profound questions about the nature of warfare and the 

morality of fighting in ways that create asymmetrical 

risks between opposing belligerents. Concerned citizens, academics, journalists, nongovernmental organizations, and policymakers have spoken out against 

drones and called for them to be strictly regulated or 

even prohibited.1 This level of public concern is evidence that the future of drone warfare not only hinges 

on technical innovations, but also on careful analysis 

of the moral and political dimensions of war. Regardless of whether drones are effective weapons, it would 

be difficult to sanction their use if they undermine the 

legitimacy of U.S. military forces or compromise the 

foundations of democratic government. 

One key challenge raised by many critics of unmanned aerial vehicles (UAVs) specifically, and unmanned systems more generally, is that removing 

American soldiers from the battlefield could disrupt 

civilian attitudes toward the use of military force in 

ways that promote war and undermine democratic accountability. Casualty aversion, which we understand 

to be the civilian public’s discomfort with sustaining 

military casualties and resistance against costly mili-
2

tary operations, is a powerful constraint on when and 

how wars are waged in democratic societies. Policymakers, and even some high-ranking commanders 

within the military, may feel pressured by public 

opinion to wage wars in ways that minimize the risk 

to soldiers or to avoid fighting when casualties are 

likely. One of the most popular and plausible arguments against the use of drones is that these weapons 

subvert the constraints created by casualty aversion in 

dangerous ways. Drones may allow wars to be waged 

without risk to human soldiers and therefore without 

the risk of provoking public backlash.

Although the argument that drones will subvert 

casualty aversion is one of the most common objections raised against these weapons, it has not been 

subjected to systematic empirical investigation. It is 

generally substantiated with inferences drawn from 

past wars and with purely theoretical accounts of how 

drones may promote civic disengagement. We tested 

this argument with survey experiments involving 

over 3,000 participants in the United States recruited 

from Amazon’s Mechanical Turk online labor market. 

Participants were randomly assigned to read information about fictional conflict scenarios. These scenarios 

varied the type of attack by U.S. forces, describing it 

as drone strikes, strikes from manned aircraft, or the 

use of ground troops. They also systematically altered 

the strategic goals of the military mission, which included counterterrorism, humanitarian intervention, 

the restraint of an aggressive foreign power, and foreign policy restraint, and support for an ally facing an 

internal military threat to its hold on power.

Our results show that participants are more willing to support the use of force when it involves drone 

strikes. Support for attacks increases noticeably when 
3

it is described as a drone strike. However, this technology’s influence on support for military interventions may not be as profound as critics of drone warfare often argue. Indeed, one important shortcoming 

of philosophical and ethical reflections on the effects 

of drones is that they do not produce very precise 

estimates about how sizable a change in opinion the 

introduction of this technology will create. One important contribution of our results, then, is to compare 

how drones alter opinions compared to other factors 

that we know from existing research alter support for 

the use of force. Casualty aversion is one of several 

considerations that affect support for war, such as 

mission type and existing attitudes about war. Demographic characteristics like gender, race, income, and 

age were also included in our analysis, with gender 

having an influence on support for war that was comparable to using drones. Thus, participants were more 

likely to support wars that posed lower levels of risk 

to American soldiers, but they were also more likely 

to support wars in pursuit of important objectives 

(especially for counterterrorism), when they thought 

that war was generally an effective foreign policy tool, 

or when they were male. This suggests that critics of 

drones are correct in calling attention to the risk of 

drones lowering inhibitions against war, but that this 

shift in attitudes is unlikely to have a strong effect on 

the incidence of wars. 

Our analysis proceeds in five stages. First, we provide an overview of the research on casualty aversion 

and explore the reasons why low casualty tolerance 

may limit wars in both jus ad bellum and jus in bello 

senses. Second, we discuss arguments that drones 

may circumvent casualty aversion in ways that lead to 

an increased incidence of war and undermine demo-
4

cratic accountability. We also raise the possibility that 

lowering inhibitions against war could have beneficial 

consequences by making it easier to engage in humanitarian interventions. Third, we explain our research 

design and show how it improves on aggregate polling data when assessing support for military interventions involving drones. Fourth, we present our results 

and discuss their implications for the debate over the 

morality of drone warfare. Finally, we conclude by 

considering some of the policy implications of our research and call attention to the importance of conducting further research on dimensions of this topic that 

we were not able to test.

LITERATURE REVIEW

Drones have become the subject of intense debate 

between those who think that the weapons raise serious ethical challenges that justify their prohibition and 

those who believe they are ethically advantageous. 

Much of this debate is focused on armed unmanned 

aerial vehicles (UAVs), such as the Predator and Reaper, and on the permissibility of targeted killing. However, commentators have also made efforts to develop 

general theories of drone ethics that account for other 

kinds of unmanned vehicles that may enter service in 

the near future. Some have even speculated about the 

ethical implications of autonomous weapons,2 though 

ethical analysis of autonomous weapons is hindered 

by uncertainty about the meaning of autonomy and 

whether the military would realistically develop 

weapons that operate without human control. 

Our analysis is primarily directed at the ethical 

challenges posed by combat UAVs in particular, which 

is defined as an airframe armed with air-to-ground 
5

weapons that is controlled remotely by a pilot who is 

located outside of the combat zone. There are several 

reasons for this. First, because UAVs are already being used and play a central role in American military 

operations, the ethical issues they raise are more urgent than some of those associated with weapons that 

are not yet in service or that have not been created. 

Second, given the uncertainty about what form drones 

will take in the future and what roles they will perform, it is difficult to develop experiments that will 

reliably gauge public opinion about them. Finally, our 

findings about UAVs may be generalizable to other 

types of aerial drones, as well as to drones operating 

on land and at sea, that have similar capacities for distancing their controllers from the battlefield and protecting them from being attacked. As discussed later, 

there is good reason to believe that our findings related to UAVs will hold true for other types of drones. 

Despite the broad range of issues taken up in the 

debate over the ethics of drone warfare and the many 

different perspectives that have been offered, one 

question has emerged as a central point of contention: 

will drones lower inhibitions against using military 

force in future conflicts? Commentators on both sides 

of the debate over drone use have reflected on this 

question and given reasons for thinking that drones 

may lower civilians’ inhibitions against fighting, raise 

new ones, or fail to significantly alter them in one way 

or another. With limited empirical data on drone usage available, most commentators have sought to substantiate their answers to this question by theorizing 

the causal mechanisms that might account for drones 

altering attitudes about the use of military force. Although the causal mechanisms that have been posited 

in previous research cannot provide a clear answer to 
6

questions about the consequences of drone use, they 

do provide a strong starting point for developing the 

hypotheses that we will test. 

Casualty Aversion as a Constraint on War.

By far the most common concern expressed by opponents of drone warfare is that drones may make it 

easier to use military force by obviating the need for 

risking human combatants’ lives in combat. This line 

of argument generally starts from the premise that casualty aversion helps to constrain wars ad bellum and 

in bello. From a jus ad bellum perspective, civilians may 

anticipate the casualties that could be sustained in a 

prospective war and oppose the use of military force 

to avoid the loss of life. Civilian support for an ongoing war might also wane as losses mount, thereby 

making it difficult to continue fighting in the aftermath 

of costly actions. From a jus in bello perspective, civilians may oppose intensifying wars, extending them 

geographically, or engaging in certain types of operations when these changes in the conduct of war may 

result in heavy casualties. Low casualty tolerance may 

therefore help to limit the occurrence of wars, compel 

belligerents to seek peace more quickly, and prevent 

conflict escalation.

There is a great deal of empirical support for the 

belief that casualty aversion helps to prevent or constrain wars. Multiple studies have found evidence indicating that civilians, especially those who are citizens 

of liberal democracies, tend to disapprove of wars that 

result in heavy casualties.3 Other studies have made 

the complementary discovery that democratic leaders are vulnerable to drops in public support that can 

be triggered by costly wars.4 These findings also hold 
7

a great deal of intuitive appeal because they seem to 

cohere with changes in public support for American 

military ventures since World War II. For example, 

low casualty tolerance explains how civilian opposition to U.S. military involvement in Vietnam and 

Somalia, following costly combat operations like the 

Tet Offensive and the Battle of Mogadishu, may have 

precipitated withdrawals from those countries, even 

when U.S. forces had a significant military advantage 

over their opponents.

Some question the power of casualty aversion and 

contend that there is not simply a linear increase of 

opposition to war as more soldiers are wounded and 

killed. Gelpi et al.

5

 argue that many considerations affect casualty tolerance, though the prospect of success 

seems to be the most important:

[W]hen it comes to supporting an ongoing military 

mission in the face of a mounting human toll, expectations of success matter the most. Many factors—the 

stakes, the costs (both human and financial), the trustworthiness of the administration, the quality of public 

consensus on the foreign policy goal in question, and 

so on—affect the robustness of support. But the public’s expectation of whether the mission will be successful trumps other considerations.6

This suggests that casualty aversion may vary considerably, depending on the type of war being fought.

Others question the reality of casualty aversion 

and contend that this phenomenon is largely based on 

false perceptions. Eric Larson finds that: 

[a]s a result of the Gulf War, the public does not expect—and is unlikely to demand—that all future U.S. 

military operations be bloodless. Indeed, it is more 

accurate to say that the public hopes for low-to-no casualty operations but fears a very different outcome.7
8

Similarly, Charles Hyde argues that casualty aversion 

is a myth and says that “[t]he public has consistently 

operated within the realm of an ends and means evaluation with significant cues from political leaders who 

frame the public debate.”8

 Casualty aversion may be 

closely linked to media coverage that focuses disproportionately on anti-war sentiments when soldiers are 

killed, as this kind of coverage may erode public support or create the false appearance of a drop in support even when real attitudes are fairly stable.9

Regardless of whether it is constant or variable, 

real or imagined, casualty tolerance does seem to be 

a consideration that civilian politicians and military 

leaders bear in mind when considering how and when 

to use military force.10 Even Hyde, who describes casualty aversion as a myth, finds that there is “strong 

evidence that policymakers and senior military leaders believe the American public is casualty averse and 

will not tolerate deaths except when vital interests are 

at stake.”11 Low casualty tolerance may therefore be 

expected to create ad bellum and in bello inhibitions 

that limit the incidence of wars and their intensity 

either because of direct pressure from the public or 

because of a perceived risk of public opposition. In 

either case, the resultant pressure may compel politicians and military leaders to seek nonmilitary strategies of conflict resolution or to at least use the utmost 

restraint when fighting. 

Drones and the Future of Risk-Free War.

To their critics, drones seem to circumvent the restrictions of casualty aversion. They make it safer for 

armed forces to wage wars without exposing their soldiers to the hazards of the battlefield, thereby mitigat-
9

ing the possibility that casualty aversion, whether real 

or perceived, will influence the decisions of politicians 

and military leaders. Moreover, critics worry that if 

drones allow the U.S. military to wage wars free of the 

risk of military casualties, they will further shift the 

burdens of war onto foreign populations. This may 

result in more wars, more foreign casualties, more environmental destruction, and more social and political 

disruption in contested areas, all without provoking 

much domestic opposition. 

John Kaag and Sarah Kreps argue that “drones create a ‘moral hazard’ by shielding US citizens, politicians, and soldiers from the risks associated with targeted killings.”12 Without risk, civilians and soldiers 

alike may be unable to understand the consequences 

of war. This may lead them to see war as a cheap and 

effective solution to complex political disputes that 

could be more effectively solved through peaceful 

means. The ethical principles that inform judgments 

about war may even lose their power when these are 

weighed against the compelling practical advantages 

of using drones. Kaag and Kreps suggest that this 

freedom from consequences may lower the threshold 

for initiating wars and make it easier to sustain protracted wars that might otherwise be forced to a conclusion by declines in public support. They are also 

concerned that drones may make it easier to wage 

wars in ways that are ethically and legally questionable, as evidenced by the use of UAVs to carry out 

targeted killings in countries with which the United 

States is not at war.

By Kaag and Kreps’ estimation, the moral hazard 

of drones is not merely a possibility, but a likely outcome given the incentive structure that shapes politicians’ decisions. Drones are attractive to politicians 
10

who may see war as a way of achieving their foreign 

policy goals but whose power is threatened by any 

shifts in public opinion that a costly war might cause. 

The use of drones provides a win–win proposition 

for the president, who could appear strong on defense 

without responsibility for body bags coming home, 

a development that would likely send his political 

fortunes tumbling.13

Kaag and Kreps contend that politicians are likely to 

increase their reliance on drone weapons over time, 

since those who fail to do so will be met with public 

opposition and risk losing office. 

Even more seriously, Kaag and Kreps think that 

the incentive structure drones create could ultimately 

have deleterious effects on the U.S. Government by 

making it possible for politicians to wage wars without securing public approval: 

Ironically, the pressure from a democratic electorate 

to protect itself from the harms of warfare will not 

encourage policy makers to adopt peaceful or democratic methods . . . but rather methods of warfare that 

leverage technology in order to insulate citizen-soldiers from harm. The irony is this insulation creates 

the possibility that leaders will no longer, in a prudential sense, have to obtain popular permission to go 

to war.14

The threat of de-democratization exacerbates the 

potential problems associated with drone use and 

suggests that even Americans who are unconcerned 

with the effects U.S. military operations have abroad 

should be alert to the possibility that overcoming casualty aversion could erode democratic governance. 
11

Kaag and Kreps’ concern over the loss of democratic accountability builds on a point previously 

made by P. W. Singer, who describes drones as being part of a larger process of de-democratizing war 

as armed forces increasingly fight in ways that evade 

public accountability.

Unmanned systems represent the ultimate break between the public and its military. With no draft, no 

need for congressional approval (the last formal declaration of war was in 1941), no tax or war bonds, and 

now the knowledge that the Americans at risk are 

mainly just American machines, the already lowering 

bars to war may well hit the ground. A leader needn’t 

carry out the kind of consensus building that is normally needed before a war, and doesn’t even need to 

unite the country behind the effort.15

Singer goes on to describe a collapse of civic engagement as the low costs of war lead decisions about 

the use of military force to become routine policy decisions that provoke little serious public deliberation. 

By his reasoning, drones will reduce war to a spectator activity as “the checks and balances that undergird 

democracy go by the wayside.”16 Thus, like Kaag and 

Kreps, Singer sees casualty aversion as a powerful 

mechanism for limiting war that has implications for 

reducing aggression and sustaining accountability. 

Frank Sauer and Niklas Schörnig17 contend that 

drones are attractive weapons for democratic states 

for procedural and normative reasons. Procedurally, democratic leaders can be punished for waging 

wars that result in heavy casualties by being removed 

from office. This compels them to seek the least costly 

methods of conflict resolution that are available and to 

avoid war whenever possible. Normatively, democra-
12

cies place a high value on human life, especially the 

lives of their own citizens, which provides added incentive to avoid violence. Sauer and Schörnig argue 

that these concurrent influences usually compel democracies to act peacefully, but that democracies may 

escape these restrictions when they are able to wage 

wars either without sustaining casualties or without 

appearing to do so.

Many techniques are available to democracies attempting to minimize the costs of war. They can employ special operations forces or private military contractors that may suffer fewer or less visible casualties. 

They can also launch guided missiles, which have the 

advantage of not endangering human combatants on 

the attacker’s side. However, Sauer and Schörnig describe drones as the “preferred solution” to the casualty tolerance problem because drones are relatively 

cheap, do not put the military personnel operating 

them at risk, and are militarily effective. Sauer and 

Schörnig share Kaag and Kreps’ concern that drones 

will make it easier for states to engage in risk-free warfare and to evade accountability. They also contend 

that this problem is apt to follow a slippery slope. As 

drones make wars safer for the militaries armed with 

them, they will become more pervasive and more 

autonomous, which will, in turn, lead to even lower 

inhibitions against using force and increased demand 

for drones. 

Daniel Brunstetter and Megan Braun18 speculate 

that drones could have the paradoxical effect of simultaneously making major wars less likely and small 

wars more likely. Their reasoning is that drones alter 

the considerations affecting the jus ad bellum principle 

of last resort, which requires that states pursue all 

available peaceful means of conflict resolution before 
13

employing military force. Drones help to prevent large 

wars by giving states a capacity to carry out small 

strikes that are less likely to provoke escalations than 

combat between human soldiers. However, Brunstetter and Braun contend that drones may lead states to 

deviate from the principle of last resort when power asymmetries make it possible to carry out drone 

attacks without fear of reprisal. As they explain: 

[t]he risk becomes that military leaders will bypass 

nonlethal alternatives, such as apprehending alleged 

terrorists and continued surveillance, and move 

straight to extrajudicial killing as the standard way of 

dealing with the perceived threat of terrorism.19

The perception that drones are more discriminate 

than other weapons exacerbates this problem by making it possible to present drone strikes as a form of 

controlled violence that is less serious than war.

Many other writers also express concerns about 

drones’ effects on civilians’ attitudes about war, 

though usually without going into as much detail 

about the exact mechanisms underlying this process. 

Linda Johansson argues that: 

[w]eapons such as UAVs, that are perceived to provide an almost guaranteed upper hand, may also 

make people believe that the war would be without 

risk, at least regarding the number of casualties

and concludes that “[t]his might have an impact on 

domestic opinion, and, in turn, lower the threshold of 

entering and sustaining a war.”20 Christian Enemark21

likewise expresses concern over what war may be 

like in the future as more states and nonstate actors 

develop unmanned weapons. 
14

The prospect of increased availability of armed drones 

warrants contemplation of a future in which the resort 

to force is less constrained by the expectation of loss, 

and this sits uneasily with ethical principles that have 

traditionally set a high threshold for going to war.22

Enemark argues that drones have already demonstrated this capacity for lowering inhibitions against 

war and that this is evidenced by the U.S. preemptive 

war against potential terrorist threats.23

David Dunn24 reflects on the way drones have altered casualty calculations in the War on Terror, with 

the effect of incentivizing more lethal strategies. 

By disembodying these weapons platforms, the technology enables their use with domestic political impunity, minimal international response and low political risk and cost. It is now politically and technically 

easier to kill suspected terrorists than to arrest them.25

Boyle26 raises a similar point by suggesting that superpowers that were once afraid to fight each other for 

fear of triggering nuclear war might suddenly find it 

easier to come into conflict using drones. He reasons 

that drones could cause subtle provocations, such as 

reconnaissance missions and small attacks, that would 

risk escalating into more serious confrontations. Finally, Gurcan27 argues that drones may make deterrence 

more difficult, as aggressors armed with drones may 

not be easy to intimidate if they can fight without sustaining casualties. This reasoning indirectly relies on 

assumptions about casualty aversion, since one of the 

goals of deterrence may be to convince civilian populations that a prospective war will be too costly to be 

worthwhile.
15

Can Risk-Free War be Ethically Advantageous?

Many commentators who defend drones agree 

with critics in thinking that drones may circumvent 

casualty aversion, yet they draw much different conclusions from this premise. Rather than seeing the 

decline in military casualties as a mechanism for overcoming inhibitions against the use of military force, 

defenders of drones tend to think that lower casualty 

rates will make it easier to promote compliance with 

the norms of just war. Zach Beauchamp and Julian 

Savulescu28 give two reasons for thinking that lowering the threshold for initiating wars may be a positive 

development. First, this may make states more inclined to fight humanitarian conflicts. If states do not 

have to risk their own forces, they will be free to wage 

benevolent wars that do not yield strategic benefits 

without facing public backlash. Second, Beauchamp 

and Savulescu argue that being freed from the fear 

of sustaining casualties will allow intervening states 

to show higher levels of restraint when fighting. This 

lends additional support to the use of drones in humanitarian wars, as it suggests that drones may be 

used in ways that coincide with the values of human 

security and respect for civilian immunity, which help 

to justify humanitarian missions.

The points raised by Beauchamp and Savulescu, 

particularly the second, coincide with those made by 

others who think that drones can be ethically advantageous. Strawser29 argues that armed forces have an obligation, which he calls the Principle of Unnecessary 

Risk, to prevent their personnel from being exposed 

to avoidable risks. By this account, it would be unethical for armed forces that have drone technology to fail 
16

to use this technology as a way of protecting soldiers. 

Moreover, Bradley Strawser and others call attention 

to the benefits this may have for civilians. Freeing 

armed forces from the concern over sustaining casualties could allow them to establish much stricter rules 

of engagement that might help to reduce violence 

against civilians.30 Drones do not face the same need 

to act in self-defense as human combatants do. Their 

operators could be prohibited from using lethal force 

whenever there is a high risk of inadvertently harming 

civilians without raising any corresponding danger to 

military personnel. Drones might therefore be a way 

of escaping the ethical dilemma of whether to prioritize force protection or civilian protection, which has 

hitherto presented an insurmountable challenge for 

just war theorists.31

These arguments in defense of drones show that 

any effect these weapons have on casualty aversion 

can be read in much different ways, depending on 

whether casualty aversion is seen as a constraint on 

war or a way of facilitating the just conduct of wars. 

This makes it vital for analyses of how drones influence casualty tolerance to account for the different 

types of wars that drones may be used in, as well as 

whether drones are used in ways that increase or decrease the risks to civilians. We do this in our experiments by testing support for drone strikes, air strikes, 

and ground attacks in pursuit of four different principal policy objectives: foreign policy restraint, counterterrorism, humanitarian intervention, and internal political change. Before turning to these experiments, we 

first discuss how some of the points raised earlier are 

reflected in public opinion surveys regarding the conflict with the Islamic State armed group in 2014. The 

debate about American military intervention against 
17

the Islamic State included discussions not only of the 

wisdom of intervening, but also the merits of different types of military action. It thus provides a contemporary opportunity to assess how the availability of 

drone technology influences public attitudes. 

Public Opinion and the Islamic State.

The United States experienced public debates 

about the wisdom of American action against Islamic 

State militants in Iraq and Syria during the summer 

and fall of 2014. Much of this debate centered on the 

type of military action, if any, the United States should 

undertake. A number of public opinion organizations polled representative samples of the American 

public and asked the degree to which they favored 

or opposed a range of steps being considered by the 

United States. 

Consider the data in Figure 1, which summarizes 

responses to questions about favoring or opposing 

different types of intervention in the conflict. A sizable 

majority of respondents favored air strikes in Syria and 

in Iraq, while far fewer supported the introduction of 

American ground troops. This is consistent with the 

argument that technologies that reduce the costs of 

conflict by placing fewer military personnel at risk of 

harm, such as drones and air power, should lead to 

increased support for the use of force. Note, however, 

that the option of sending military advisors to Iraq receives almost as much support as does the use of air 

power. This is a bit puzzling from this perspective, as 

military advisors may be in proximity to Iraqi ground 

troops who engage in combat. Note as well that training and equipping rebels in Syria, which presumably 

would not risk combat by Americans, receives consid-
18

erably less support. Why might this be the case? One 

explanation might be that the public also incorporates 

its beliefs about the likelihood that the use of force 

will succeed in achieving its goals against its human 

and financial costs. It is possible that respondents recognized that sending military advisors to Iraq would 

place them in harm’s way, but balanced this against 

the belief that advisors could bolster the effectiveness 

of Iraqi ground units against the rebels. They may also 

have concluded that arming Syrian rebels, who had 

proven incapable of either overthrowing the Assad 

regime or stopping the rise of the Islamic State, would 

be an ineffective strategy. 

Notes: Data from CBS/The New York Times public opinion survey released September 17, 2014. Totals do not equal 100 due to 

rounding.

Figure 1. Support for Military Action, 

September 2014.
19

Some evidence for this comes from comparing the 

information in Figures 2 and 3, which summarize responses to questions about preferences for different 

combinations of air power. Figure 2 depicts responses 

to questions that asked respondents if they favored the 

use of drones and manned aircraft in striking the Islamic State. Drone strikes received considerably more 

support than attacks from manned aircraft, which is 

consistent with the argument that reducing the costs 

of war increases support for the use of force. From this 

perspective, though, the results of a poll conducted at 

approximately the same time are surprising. As can 

be seen in Figure 3, a much higher percentage of respondents prefer strikes from platforms that do not 

risk American lives—drones and cruise missiles—

than from piloted aircraft. However, an even larger 

percentage prefer strikes from both types of weapons 

systems. This might be because such combined strikes 

are seen as more effective than the use of only one 

weapons system. 

Notes: Data from CBS/The New York Times public opinion 

survey released June 23, 2014.

Figure 2. Preferences for Strikes from Manned 

Aircraft and Drones, June 2014.
20

Notes: Data from Quinnipiac public opinion survey released 

July 3, 2014.

Figure 3. Preferences for Strikes from Manned 

Aircraft and Drones, June 2014.

This public opinion data, then, does not reveal an 

obvious pattern in which attacks that reduce the likelihood of an important cost of war—military casualties—receive more public support. It is important to 

recognize, though, that such polls are not really designed to directly assess specific propositions about 

how changes in the costs of war influence attitudes. 

To see why this is the case, return to Figure 1. We suggested that one reason respondents in this survey expressed strong preferences for sending military advisors to Iraq was that they believed that doing so would 

increase the combat effectiveness of Iraqi units while 

exposing American military personnel to acceptably 

Don't Know/ No Airstrikes

No Answer
21

small risks of harm. But other interpretations are plausible; for example, perhaps many respondents believe 

that advisors would face very small risks roughly 

equal to those of aircraft crews launching attacks in 

uncontested air space. The questions in this and most 

public opinion surveys are intended to measure support for various options, not to assess directly why 

respondents express the preferences that they do. Yet 

doing so is important for establishing which of the 

propositions about how changes in the cost of conflict 

influence public support for the use of force. In the 

next section, we argue that an experimental approach 

is better-suited for this purpose, and summarize results from a series of experiments that are designed to 

directly test such propositions. 

Survey Experiment.

To answer these types of questions, we conducted 

a survey experiment in early 2015. This experiment recruited participants from Amazon’s Mechanical Turk 

online labor market. Mechanical Turk is an inexpensive and flexible way to enlist participants, and has 

become a widely used tool among social scientists.32

Respondents were randomly assigned to read a mock 

news story describing plans by the United States to 

use military force overseas.33 Random assignment to 

these “treatments” is a key part of the experiment. It 

allows us to assume that the characteristics of individuals assigned to read each news story are not systematically different from each other. This means that 

we can expect that any differences in the attitudes that 

people assigned to different treatments are due to the 

content of the news stories.34
22

The news stories varied two elements (see the Appendix for the complete wording of each treatment as 

well as the questions that comprise the survey instrument). The first was the type of military action. This 

could take one of three forms: a drone strike, an air 

strike from a piloted aircraft, or the use of ground 

troops. Consistent with the casualty aversion idea discussed earlier, the news stories had different information about the risk that American military personnel 

would face. The drone treatments stated that “the use 

of unmanned drones means that no American military personnel would be placed at risk.” The air strike 

treatments, in contrast, included information that 

the target of the strikes were believed to lack weapons capable of attacking aircraft, suggesting a low 

possibility of military casualties. The ground troops 

news stories did not mention if these troops faced any 

danger or not. 

The second element that varied across the treatments was the purpose or goal of the use of force. 

Here, we follow in the footsteps of important work 

on public opinion and foreign policy which finds that 

preferences differ in important ways depending on 

the “principle policy objective” of the use of force.35

The treatments in our news story vary four such objectives. The first is counterterrorism, in which attacks 

are planned on militants who have in the past attacked the United States. The second is foreign policy 

restraint, where the United States seeks to punish a 

foreign state for threatening a key interest, in this case 

the shipment of petroleum from the Persian Gulf to 

world markets. The third is humanitarian intervention, in which American military force has the objective of stopping mass killings in a foreign country. The 

final objective is internal political change, aimed at 
23

preventing the violent overthrow of a foreign government by its internal opponents. Our mock news stories are modeled closely on those of Gelpi, Feaver, and 

Reifler36 and use the country of Yemen as the location 

of the use of force. 

Combining these two elements—type and objective 

of military force—produces a total of 12 treatments. 

Roughly 300 participants were randomly assigned to 

read each of these stories. They then answered questions about their reactions to the planned use of force, 

including the degree to which they supported the attack; their estimates of the number of military casualties that would result if the attack were carried out; 

general attitudes regarding the wisdom of the use of 

force; and demographic questions such as party identification, age, gender, and so on.

To this point, we have argued that military casualties are a very important cost of conflict that influences attitudes regarding the wisdom of using force. 

Our experiment is designed to alter systematically the 

likelihood of such casualties. We expect that participants in the experiment will expect the lowest number 

of military casualties from a drone strike, since these 

news stories make explicit the fact that military personnel will face no risk of physical harm. Treatments 

involving air strikes should lead to higher expectations of military casualties. Even though these treatments state that the target of the attack is not believed 

to have weapons capable of threatening military aircraft, participants might still expect that the chance of 

military casualties could be higher since such aircraft 

do place military personnel in a battle zone. Participants might worry that the target has, unknown to the 

United States, acquired anti-aircraft weapons, or that 

casualties could result if the aircraft were to malfunc-
24

tion over enemy territory. Participants’ expectations 

of military casualties should be highest in the treatments that describe the attack as being carried out 

by ground troops. Although these news stories make 

no mention of the risks that military personnel face 

in such situations, it should be straightforward for 

participants to infer such risks from the information 

they read.

To assess how assignment to different treatments 

influenced estimates of military casualties, participants were asked if they expected no casualties, between 1 and 10 casualties, or between 11 and 100 casualties. The black dots in Figure 4 display the average 

responses to these questions for each treatment; the 

lines connected to each dot indicate the 95 percent confidence interval surrounding these averages. We see 

a pattern, consistent with our expectations, in which 

participants assigned to the drone strike treatments 

expected the fewest casualties, followed by those assigned to air strike treatments and then the ground 

troop treatments. Differences across treatments for the 

same mission objective are sizable and statistically significant. Furthermore, differences across treatments 

for the same type of attack are not statistically different from each other. This suggests that the information 

in the treatments influenced participants’ expectations 

of the costs of conflict in terms of military casualties.
25

Figure 4. Expectation of Military Casualties.

But do such differences matter for support for 

the use of force? To answer this question, we asked 

participants to indicate the degree to which they supported the military action described in the news story 

they read. Participants could strongly disapprove, 

somewhat disapprove, somewhat approve, or strongly approve of the attack. The average responses (and 

confidence intervals) for this question are depicted 

in Figure 5. Drones lower inhibitions against initiating armed conflicts, as many critics of this technology 

have predicted. Respondents were consistently more 

likely to favor the use of UAVs over ground forces in 

each of the experiments, regardless of the objectives 

being pursued. They were also more willing to initiate 

conflicts using drones than piloted aircraft, except in 

humanitarian interventions. Furthermore, the consistent preference for air strikes over attacks involving 
26

ground forces provides evidence that support for a 

prospective operation generally increases as the likelihood of sustaining military casualties decreases. This 

indicates that American civilians are more inclined to 

support using weapons that reduce the risk of military 

casualties, regardless of whether UAVs are available, 

and that other weapons that allow U.S. forces to manage risks may produce similar shifts in support for 

launching an attack.

Figure 5. Support for the Use of Force.

Nevertheless, the differences between levels of support for the three tactics are rather small. Respondents 

were more likely to favor attacks involving UAVs over 

attacks involving piloted aircraft or ground forces, but 

on average differences in these treatments reduced the 

average degree of support from just below “somewhat 

approve” towards “somewhat disapprove.” These 

small absolute changes in public support for the three 

tactics suggests that, although UAVs may be expected 
27

to lower inhibitions against initiating wars by shielding American soldiers from risk, they are unlikely 

to increase dramatically the incidence of fighting as 

some critics of drone warfare have suggested. This 

is evidence that drones do raise legitimate concerns 

about attitudes toward initiating hostilities, but that 

these concerns must be stated far more modestly and 

that greater attention must be given to how support 

for drone use varies depending on the context. 

Choosing to use drones instead of piloted aircraft 

or ground troops may be expected to provide a small 

increase in public support for a prospective war. Even 

a small change could have a decisive influence on the 

overall level of public support for war if the country 

is narrowly divided. In other words, deciding to use 

drones to carry out an attack could tip the balance of 

a nearly even division between pro-war and anti-war 

attitudes toward the former position. On the other 

hand, if opposition to war outweighs support, then it 

appears that the use of drones to fight without the risk 

of incurring casualties would be insufficient to sway 

public opinion to support an attack. The slight influence on attitudes toward the initiation of hostilities 

suggests that although drones may diffuse concerns 

about sustaining casualties, they are unlikely to have 

a significant effect on the incidence of wars. It seems 

that unpopular wars will remain unpopular even if 

drones are able to reduce the level of opposition to 

fighting. 

Another way to assess the substantive influence of 

drones is to compare their effect to other factors that 

influence support for the use of force. Figures 6 to 9 

undertake such comparisons. Each figure reports the 

coefficients and associated confidence intervals for a 

regression model using support for the use of force as 

the dependent variable. The independent variables in 
28

each model include whether or not the participant was 

assigned to read a story about a drone strike, whether 

or not the participant read about an air strike, and the 

party identification, gender, race, income, and age of 

the participant. All of these variables were rescaled to 

range from zero to 1. This means that we can compare 

the coefficients directly to each other. The dots indicate how increasing the independent variable from its 

minimum to its maximum value influences support for 

the use of force. For example, the coefficient for drone 

strike indicates how much support changes when the 

participant reads about the use of a UAV compared 

to the use of ground troops, while the coefficient for 

air strike indicates the change in support when the 

participant is assigned to a treatment describing such 

an attack. Similarly, the coefficient for the female variable indicates the change in support when the participant is a woman compared to a male participant. 

The figure for party identification indicates the difference between participants that self-identify as “strong 

Democrat” and “strong Republican.”37

Figure 6. Coefficients for Counterterrorism 

Treatments.
29

Figure 7. Coefficients for Foreign Policy Restraint 

Treatments.

Figure 8. Coefficients for Humanitarian 

Intervention Treatments.
30

Figure 9. Coefficients for Internal Political Change 

Treatments.

We see that the effect of describing an attack as a 

drone strike is roughly similar in magnitude to the effect of gender, and smaller or about the same size as 

party identification. Both of these factors have wellestablished influences on support for the use of force 

and attitudes towards public policy more generally. 

Pamela Conover and Virginia Sapiro38 find that gender 

is one of the most consistent and powerful influences 

on attitudes regarding military action.39 Similarly, a 

large number of studies have concluded that party 

identification has been shown to have a large effect on 

attitudes towards many types of public policy.40 The 

fact that the substantive influence of drone strikes, 

compared to ground troops, is of a similar size to the 

effects of gender and party identification indicates 

that this weapon could have an effect on attitudes that 

matters at the margin.
31

In practice, the effects of the slight shifts in public 

opinion that may be produced by using ground forces, piloted aircraft, or drones may not directly affect 

whether a particular war is waged. Decisions about 

initiating wars are not made directly by the American 

public but rather by elected officials whose decisions 

may be insulated from citizens’ attitudes or unresponsive to them. Thus, public opinion will matter to the 

extent that changes in it can influence policymakers 

and alter their decisions. Voters may decide to punish 

policymakers who wage unpopular wars by removing 

them from office.41 However, it seems unlikely that the 

shifts in public opinion that may be caused by using 

UAVs instead of ground forces or piloted aircraft will 

always have great influence on policymakers’ decisions if they are determined to go to war. An increase 

in opposition may not greatly influence a policymaker’s election prospects, especially when it is 

weighed against other decisions that person has made 

and that will also influence voter preferences. 

The effect UAVs have on support for war is likely 

to make them attractive weapons for politicians who 

are concerned with maintaining their approval ratings during conflicts. The shift in public support that 

drones produce may not be enormous and may not be 

sufficient to cause a decisive change in the balance of 

public opinion about a war, yet it is nevertheless just 

one of the many advantages that make drones attractive weapons. As Sauer and Schörnig correctly point 

out, there are multiple reasons for preferring drones 

over other weapons and tactics, such as their ability to 

loiter over targets and their comparatively low cost.42

Nevertheless, based on our experiment, it appears that 

the predictions Singer43 and Kaag and Kreps44 make 

about drones undermining democratic accountabil-
32

ity are probably too strong. Because drones produce 

moderate increases in support for war, greater reliance on them will probably be unable to silence antiwar voices. At least some politicians will continue to 

have strong incentives to pursue peaceful strategies of 

conflict resolution in an effort to satisfy those citizens 

who are unwilling to support military operations even 

if they exact a low human cost. 

The pattern that is evident in the levels of support 

for using drones, piloted aircraft, and ground forces 

shows that there is a continuum of support for military force that extends across the range of weapons 

and tactics that may be employed. One possibility for 

future research is to include a more diverse assessment 

of the weapons and tactics used by the U.S. military to 

see the extent to which this pattern is sustained. There 

may be gradations of support between the three types 

of attacks we explore. For example, support for the 

use of special operations forces could fall somewhere 

between support for an attack involving conventional 

ground forces and an air strike. Alternatively, it is possible that support for war could further diminish or 

increase as other weapons and tactics are introduced. 

The deployment of large numbers of soldiers to directly engage in combat could be less popular than the 

deployment of smaller numbers of soldiers serving in 

advisory roles.

Nevertheless, it seems that our study has reached 

a limit when it comes to how drones may increase 

support for war by circumventing casualty aversion. 

The UAVs that were discussed in our experiments 

provide their pilots with complete protection against 

harm, as the pilots are removed from the battlefield 

and cannot be injured by any attacks on their aircraft. 

Other types of drones, such as semi-autonomous and 
33

autonomous drones, may reduce human involvement in attacks and alter public support for war, yet 

they will not do this by influencing casualty calculations. After all, more advanced drones will not be able 

to offer additional protection for American personnel 

who are already far away from the battlefield. This indicates that other types of drones may produce slight 

change in public support for using military force that 

are comparable to the shifts produced by UAVs. 

THE IMPORTANCE OF CONFLICT TYPE

The principal policy objective was an important 

predictor of participants’ willingness to conduct 

military operations. Participants were most likely to 

support the use of ground troops, piloted aircraft, or 

drones in counterterrorism operations, a finding consistent with earlier research.45 The willingness to support the use of force against terrorists seems to reflect 

the perceived threat that terrorism poses to national 

security, as well as the sense that the United States is 

actively engaged in a War on Terror, in which terrorists are legitimate military targets. Higher support for 

using drones against terrorists demonstrates the importance of distinguishing between objections to how 

UAVs are used to conduct targeted killings against 

terrorists and how they are used in other contexts. 

The higher levels of support for all three tactics in 

counterterrorism strikes is also evidence that many 

of the trends in U.S. military operations that critics 

have cited as being byproducts of drone use may be 

more accurately described as being byproducts of the 

War on Terror that may change if the U.S. military’s 

objectives change.
34

The other three principal policy objectives involved attacks on less immediate threats against enemies that the United States was not actively fighting when the experiments were conducted. In these 

instances, fewer respondents were willing to support 

a war, even if it could be waged with minimal risk 

to American soldiers. This supports previous research 

by Bruce Jentleson,46 who found that Americans were 

more likely to support attacks when an “adversary 

had gone beyond simply posing a standing threat and 

initiated aggressive actions against American interests 

or citizens” and that the public was not likely to support military operations that were directed at preventing future threats or remaking foreign governments.

The effect of conflict type on support for war suggests that the perceived necessity and morality of war 

matter to the American public, with more serious 

threats lowering inhibitions against using any type of 

force even as considerations about the expected number of American military casualties help to determine 

how an attack should be carried out. The implication 

here is that the use of drones is more likely to contribute to the case for initiating war when policymakers 

can connect drone strikes to plausible enemy threats. 

The framing of attacks will therefore help to determine 

whether drones will contribute to a greater incidence 

of wars. 

The varying levels of support for attacking under 

differing circumstances provide additional evidence 

that the effects of circumventing casualty aversion 

with weapons that reduce the likelihood of casualties 

will be fairly modest. Avoiding American military casualties is just one of the considerations that go into 

deciding whether to fight, and it may not even be 

the most salient one. It is also important to note that, 
35

despite the differing levels of support for each type 

of conflict, participants’ attitudes toward the use of 

military force were generally moderate. The average 

responses consistently fell between the “somewhat 

approve” and “somewhat disapprove” evaluations. 

The participants’ general lack of strong attitudes 

for or against war indicates that participants took a 

pragmatic attitude toward use of force decisions, according to which attacks are supported or opposed as 

considerations relating to their necessity, prospective 

costs, and ethicality change.

Perhaps the most surprising discovery was that 

support for air strikes in humanitarian interventions 

surpassed support for UAV strikes. This was the one 

instance in which the results deviated from the pattern 

of decreasing levels of support as military personnel 

were at a higher risk of being killed or injured. It is 

difficult to determine why this anomaly exists given 

the available information, especially since this pattern 

deviates so clearly from the results relating to other 

principal policy objectives. Because the pattern was 

present in experiments involving participants with 

high and low military assertiveness, this preference 

does not appear to be affected by militaristic attitudes. 

The different pattern here may be an indication that 

respondents were evaluating humanitarian interventions according to different criteria than those they 

applied to other principal policy objectives.

What is clear is that the greater support for air 

strikes, rather than drones, in humanitarian interventions conflicts with Beauchamp and Savulescu’s47 contention that drones might lower casualty aversion in 

morally advantageous ways. They argue that drones 

could promote support for humanitarian interventions by reducing the costs those operations may have 
36

on armed forces that conduct them for benevolent motives and without any expectation of compensation. 

Because support for humanitarian intervention is 

highest when piloted aircraft are used, it appears that 

these would be the optimal weapons to employ when 

intervening and that drones’ effects on casualty aversion may only be significant when the only alternative 

is the more costly use of ground forces. Of course, this 

may not be true for the many other countries that are 

developing drone weapons and that may use them 

in humanitarian missions. It is therefore important 

to withhold judgment on whether Beauchamp and 

Savulescu’s argument is accurate in general and to 

continue testing it in future research.

CONCLUSION

Our experiment has important implications for 

members of the military and policymakers. Although 

the American military plays only an advisory role 

in decisions to initiate wars, it unavoidably affects 

policymakers’ calculations about the use of military 

force and is, in turn, affected by the choices made by 

policymakers and the American public. Policymakers may have the ultimate control over when wars are 

declared, but political calculations are affected by the 

military’s decisions to develop certain offensive capacities, as well as its ability to realize those capacities 

in practice. Members of the military have a large stake 

in decisions about the resort to war, as they will be the 

ones who bear the greatest burdens during a conflict. 

Our results show that drones are unlikely to dramatically change calculations about initiating war in ways 

that would increase the incidence of fighting, yet the 

noticeable shifts in public opinion when using drones 
37

compared to other weapons reveals that the possibility of drones contributing to the overall case for military interventions cannot be disregarded. 

The U.S. military has responsibilities to its soldiers, 

civilian policymakers, and the American public that 

could potentially come into conflict when using drone 

weapons. In a sense, the concern that drones could 

lower inhibitions against the use of force is a concern 

that politicians or members of the military may violate public trust by waging unnecessary or aggressive 

wars. The military could inadvertently fail in its responsibility to protect the American public if it develops weapons that ultimately increase the prevalence 

of war, especially if wars are economically costly or 

increase the likelihood of future attacks against the 

United States. At the same time, the military has an 

obligation to protect its personnel from the dangers 

of the battlefield to the greatest extent possible, which 

will inevitably provide grounds for making greater 

use of drones and other remote weapons. 

Our results demonstrate that these obligations are 

not perfectly aligned; there is some tension between 

responsibilities toward American civilians and responsibilities toward American soldiers. Relying on 

drones to help protect soldiers from harm generally 

increases support for war in ways that could influence on the decision to use military force when public 

opinion is narrowly divided and politicians are highly 

sensitive to it. Although this is a fairly remote possibility given the complex assortment of motives that 

affect civilians’ attitudes and policymakers’ insulation 

from public pressure when initiating wars, it is an important possibility for members of the military to bear 

in mind. Decisions to expand the U.S. military’s drone 

force and to employ this technology in a greater range 
38

of combat roles should be made with some sense of 

how developing certain technical capacities might 

alter future decisions to initiate wars.

Although our experiment focused on the UAVs 

that are currently used by the U.S. Air Force and 

Central Intelligence Agency, the results speak to concerns that will affect the Army as it develops new 

unmanned weapon systems and prepares to deploy 

them in future conflicts. The Army has consistently 

worked towards improving its ethical standards since 

the Vietnam War, as evidenced by its continual reevaluations of ethics education, its efforts to promote core 

values, and the Center for the Army Profession and 

Ethics’ work developing more effective ethical training tools.48 As the Army strives to protect its values 

and promote ethical conduct in the future, it will be 

important for it to remain aware of the importance of 

ensuring that its efforts to improve force protection do 

not create new ethical challenges. Most of all, it must 

ensure that it protects American soldiers to the highest degree possible and improves its offensive capacities without inadvertently creating technologies that 

conflict with its other responsibilities. 

To a large extent, this will be a matter of effective 

public diplomacy. The Army is sensitive to the demands of engaging with civilian audiences and shaping their attitudes about the Army and its mission.49

A central part of this public diplomacy is the display 

of new weapons technologies and efforts to attract 

recruits who can operate them. The risk of inadvertently lowering barriers against war is not only linked 

to drones themselves but also to how drones are perceived. That is to say, the risk critics of drone warfare 

call attention to is the danger that a lack of American 

casualties will be confused with a sanitization of war 
39

even as wars continue to inflict terrible human suffering. The Army has an important role to play in presenting information about drones and informing the 

public about their associated risks and benefits. In 

particular, the Army should help to ensure that the 

American public does not lose sight of the fact that, 

despite the benefits drones bring in terms of force protection and offensive power, wars remain extremely 

destructive activities that must be waged for the right 

reasons and only as a last resort.

Policymakers face a different set of ethical challenges when it comes to developing and using drones. 

Although drones are unlikely to produce the kind of 

profound civic disengagement in military decisions 

that critics of drone warfare fear, these weapons nevertheless exert some influence on support for war, 

which could help policymakers build the case for war 

and escape a public backlash against costly military 

operations. Drones will be particularly important 

when they are used in conjunction with other strategies for justifying a war—for example, if a prospective 

military venture can be framed as a counterterrorism 

operation. This should not be considered a purely 

good or bad outcome. In some instances, war may be 

warranted and helping politicians make the case for 

war will be morally advantageous. At other times, a 

war may fail to pass jus ad bellum standards and any 

effect drones have in lowering inhibitions against 

fighting will be morally harmful.

Decisions about whether a war should be waged 

must be made on a case-by-case basis, which makes it 

impossible to pass final judgment on drones as being 

purely good or bad weapons. However, our results 

suggest that drones make other jus ad bellum considerations more important than ever. Differences in the 
40

principal policy objectives in our experiment showed 

that the perceived legitimacy and urgency of military 

intervention affected support for initiating hostilities. 

Unlike drones, which can lower inhibitions against 

fighting in just or unjust wars, principal policy objectives are central to determining whether war is justified. This makes it vital for policymakers to formulate 

just principal policy objectives and to state openly the 

principal policy objectives they are pursuing so these 

can be evaluated by the American public. It is critical to note that drawing out the implications of our 

findings for the military and policymakers will also 

depend on further research about how drones affect 

public opinion. The concern over drones evading the 

restrictive effects of casualty aversion can be extended 

to foreign civilians. Foreign civilian casualties may 

erode support for war just as military casualties do.50

Members of the public may lose interest in wars that 

appear to be misdirected at innocent people or that 

inflict disproportionate civilian “collateral damage.” 

This could give states an incentive to fight in ways 

that minimize the risk to foreign civilians just as they 

have an incentive to minimize military casualties. 

However, in this context the concern expressed by 

critics of drone warfare is not that drones will actually 

lower civilian casualty rates, as they may for military 

personnel, but that drones will give the appearance of 

reducing civilian victimization even as the increased 

incidence of war and new methods of fighting put 

civilians at greater risk than ever. 

Kaag and Kreps51 raise this challenge by suggesting that drones’ impressive technical capacities may 

give the misleading impression that wars are being 

waged with greater attention to the jus in bello principles of proportionality and discrimination. This could, 
41

in turn, affect citizens’ judgments relating to jus ad bellum. After all, if drones appear to improve compliance 

with the in bello rules of war, then they could also make 

the decision to wage war seem less morally significant. 

Drones might even give the appearance that the only 

casualties of war are enemy combatants. Closely related to this is the suspicion that the U.S. Government 

may already be underreporting the civilian casualties 

inflicted by drone strikes in an effort to make these 

strikes appear to be an attractive alternative to other 

types of military operations.52 By this account, drones 

may be ethically objectionable because they facilitate 

dissimulation more than other weapons.

Several studies found that public opinion does not 

seem to be strongly affected by the suffering of foreign civilian populations.53 There is evidence to show 

that democracies can inflict heavy foreign civilian casualties, and even target civilians, without sustaining 

any serious crises of public confidence.54 This research 

would suggest that drones’ capacities for creating the 

appearance of minimal civilian harm are relatively unimportant. After all, if public opinion is not sensitive 

to civilian casualties, then there is little reason to think 

that drones may reduce inhibitions against fighting by 

hiding those casualties. 

Research that is focused specifically on drone 

strikes that harm civilians suggest that the apparent 

insensitivity to foreign civilian casualties has been 

overstated. Kreps55 argues that the extent to which civilian casualties undermine support for drone strikes 

has been underestimated in polls and that it is stronger 

than the available data would suggest. She substantiates this with experiments that show how different 

ways of framing polling questions may elicit greater 

sensitivity to civilian casualties. Walsh56 finds that the 
42

anticipated number of civilian casualties has a powerful influence on attitudes toward drone strikes—even 

exceeding the intolerance for sustaining military casualties—and that sensitivity to civilian casualties appears to be higher when they are inflicted using precision weapons. This is evidence that the use of drones 

and other precision weapons may prime people to 

expect lower civilian casualty rates and cause them to 

adjust their willingness to condone them. 

ENDNOTES

1. Medea Benjamin, Drone Warfare: Killing by Remote Control, 

New York: OR Books, 2012; Sarah Kreps and John Kaag, “The 

Use of Unmanned Aerial Vehicles in Asymmetric Conflict: Legal 

and Moral Implications,” Polity, Vol. 44, No. 2, 2012, pp. 260-285; 

John Kaag and Sarah Kreps, Drone Warfare, Malden, MA: Polity 

Press, 2014.

2. Robert Sparrow, “Killer Robots,” Journal of Applied Philosophy, Vol. 24, No. 1, 2007, pp. 62-77; Ronald C. Arkin, Governing 

Lethal Behavior in Autonomous Robots, Boca Raton, FL: Taylor & 

Francis Group, 2009; Armin Krishnan, Killer Robots: Legality and 

Ethicality of Autonomous Weapons, Burlington, VT: Ashgate, 2009; 

Aaron Johnson and M., Sidney Axinn, “The Morality of Autonomous Robots,” Journal of Military Ethics, Vol. 12, No. 2, 2013, pp. 

129-141; Marcus Schulzke, “Autonomous Weapons and Distributed Responsibility,” Philosophy and Technology, Vol. 26, No. 2, 

2013, pp. 203-219.

3. John E. Mueller, War, Presidents and Public Opinion, New 

York: Wiley, 1973; Edward N. Luttwak, “Towards Post-Heroic 

Warfare.” Foreign Affairs, Vol. 74, No. 3, 1995, pp. 109–122.

4. Bruce Bueno de Mesquita and Randolph M. Siverson, “War 

and the Survival of Political Leaders: A Comparative Study of Regime Types and Political Accountability,” The American Political 

Science Review, Vol. 89, No. 4, 1995, pp. 841-855. Louis Klarevas, 

“Trends: The United States Peace Operation in Somalia,” Public 

Opinion Quarterly, Vol. 64, No. 4, 2000, pp. 523–540; Louis Klare-
43

vas, “The ‘Essential Domino’ of Military Operations: American 

Public Opinion and the Use of Force,” International Studies Perspectives, Vol. 3, No. 4, 2002, pp. 417-437; Scott Sigmund Gartner, 

“The Multiple Effects of Casualties on Public Support for War: An 

Experimental Approach,” American Political Science Review, Vol. 

102, No. 1, 2008, pp. 95-106; M. A. Baum, and T. Groeling, “Reality 

Asserts Itself: Public Opinion on Iraq and the Elasticity of Reality, 

International Organization, Vol. 64, 2010, pp. 443-479; Douglas Kriner and Francis Shen, “Responding to War on Capitol Hill: Battlefield Casualties, Congressional Response, and Public Support for 

the War in Iraq,” American Journal of Political Science, Vol. 58, No. 

1, 2014, pp. 157-174; H. E. Goemans, “Fighting for Survival: The 

Fate of Leaders and the Duration of War,” The Journal of Conflict 

Resolution Vol. 44, No. 5, 2000, pp. 555-579; David L. Rousseau, 

Trevor Thrall, Marcus Schulzke, and Steve S. Sin, “Democratic 

Leaders and War: Simultaneously Managing External Conflicts 

and Domestic Politics,” Australian Journal of International Affairs,

Vol. 66, No. 3, 2012, pp. 349-364.

5. Christopher Gelpi, Peter D. Feaver, and Jason Reifler, “Success Matters: Casualty Sensitivity and the War in Iraq,” International Security, Vol. 30, No. 3, 2006, pp. 7-46; Christopher Gelpi, 

Peter D. Feaver, and Jason Reifler, Paying the Human Costs of War: 

American Public Opinion & Casualties in Military Conflicts, Princeton, NJ: Princeton University Press, 2009.

6. Gelpi, Feaver, and Reifler, Paying the Human Costs of 

War, p. 2.

7. Eric V. Larson, Casualties and Consensus: The Historical Role 

of Casualties in Domestic Support for U.S. Military Operations, Santa 

Monica, CA: RAND, 1996, p. 101.

8. Charles K. Hyde, Casualty Aversion: Implications for Policy Makers and Senior Military Officers, Newport, RI: Naval War 

College, 2000, p. 10.

9. Cori Dauber, “Image as Argument: The Impact of Mogadishu on U.S. Miltiary Intervention,” Armed Forces & Society, Vol. 27, 

No. 2, 2001, pp. 205-230; Cori Elizabeth Dauber, “The Shot Seen 

‘Round the World’: The Impact of the Images of Mogadishu on 

American Military Operations,” Rhetoric & Public Affairs, Vol. 4, 

No. 4, 2001, pp. 653-687.
44

10. Douglas Kriner and Francis Shen, “Responding to War on 

Capitol Hill: Battlefield Casualties, Congressional Response, and 

Public Support for the War in Iraq,” American Journal of Political 

Science, Vol. 58, No. 1, 2014, pp. 157-174.

11. Charles K. Hyde, Casualty Aversion: Implications for Policy Makers and Senior Military Officers, Newport, RI: Naval War 

College, 2000.

12. Kaag and Kreps, Drone Warfare, p. 2.

13. Ibid., p. 65.

14. Ibid., p. 76. 

15. P. W. Singer, Wired for War: The Robotics Revolution and 

Conflict in the 21st Century, New York, Penguin Press, 2009, p. 255.

16. Ibid., p. 258.

17. Frank Sauer and Niklas Schörnig “Killer Drones: The ‘Silver Bullet’ of Democratic Warfare?” Security Dialogue, Vol. 43, No. 

4, 2012, pp. 363-380.

18. Daniel Brunstetter and Megan Braun, “The Implications of 

Drones on the Just War Tradition,” Ethics & International Affairs,

Vol. 25, No. 3, 2011, pp. 337-358.

19. Ibid., p. 346.

20. Linda Johansson, “Is It Morally Right to Use Unmanned 

Aerial Vehicles (UAVs) in War?” Philosophy & Technology, Vol. 24, 

No. 3, 2011, p. 283.

21. Christian Enemark, Armed Drones and the Ethics of War: 

Military Virtue in a Post-Heroic Age, New York: Routledge, 2013.

22. Ibid., p. 23.

23. Ibid; Christian Enemark, “Drones over Pakistan: Secrecy, 

Ethics, and Counterinsurgency,” Asian Security, Vol. 7, No. 3, 

2011, pp. 218-237.
45

24. David Hastings Dunn, “Drones: Disembodied Aerial Warfare and the Unarticulated Threat,” International Affairs, Vol. 89, 

No. 5, 2013, pp. 1237-1246.

25. Ibid., p. 1238.

26. Michael J. Boyle, “The Costs and Consequences of Drone 

Warfare,” International Affairs, Vol. 89, No. 1, 2013, pp. 1-29.

27. Metin Gurcan, “Drone Warfare and Contemporary Strategy Making: Does the Tail Wag the Dog?” Dynamics of Asymmetric 

Conflict: Pathways Toward Terrorism and Genocide, Vol. 6, No. 1-3, 

2013, pp. 153-167.

28. Zack Beauchamp and Julian Savulescu, “Robot Guardians: Teleoperated Combat Vehicles in Humanitarian Military 

Intervention,” Bradley Jay Strawser, ed., Killing by Remote Control: 

The Ethics of an Unmanned Military, New York: Oxford University 

Press, 2013.

29. Bradley Jay Strawser, “Moral Predators: The Duty to 

Employ Uninhabited Aerial Vehicles,” Journal of Military Ethics,

Vol. 9, No. 4, 2010, pp. 342-368.

30. Ronald C. Arkin, Governing Lethal Behavior in Autonomous 

Robots, Boca Raton, FL: Taylor & Francis Group, 2009; Strawser, 

“Moral Predators,” pp. 342-368; Marcus Schulzke, “Robots as 

Weapons in Just Wars,” Philosophy and Technology, Vol. 24, No. 

3, 2011, pp. 293-306; Marcus Schulzke, “The Morality of Remote 

Warfare: Against the Asymmetry Objection to Remote Weaponry,” Political Studies, 2014; Anton Petrenko, “Between Berserksgang and the Autonomous Weapons Systems,” Public Affairs 

Quarterly, Vol. 26, No. 2, 2012, pp. 81-102.

31. Michael Walzer, Just and Unjust Wars: A Moral Argument 

with Historical Illustrations, New York: Basic Books, 1977, pp. 155-

157; Jeff McMahan, “The Just Distribution of Harm between Combatants and Noncombatants,” Philosophy & Public Affairs, Vol. 38, 

No. 4, 2010, pp. 342-379.

32. Adam J. Berinsky, Gregory A. Huber, and Gabriel S. Lenz, 

“Evaluating Online Labor Markets for Experimental Research: 
46

Amazon. com’s Mechanical Turk,” Political Analysis, Vol. 20, 2012, 

pp. 351–368; T. S. Behrend, D. J. Sharek, A. W. Meade, and E. N. 

Wiebe, “The viability of crowdsourcing for survey research,” 

Behavior Research Methods, Vol. 43, No. 3, 2011, pp. 800–813.

33. A total of 3,784 individuals participated in the experiment. Each participant was paid $.40. The survey was conducted 

in January 2015. The resulting data, and code used to generate the 

results reported here are available from www.jamesigoewalsh.com.

34. B. J. Gaines, J. H. Kuklinski, and P. J. Quirk, “The Logic 

of the Survey Experiment Reexamined,” Political Analysis, Vol. 15 

No. 1, 2007, pp. 1–20.

35. Bruce W. Jentleson, “The Pretty Prudent Public: Post PostVietnam American Opinion on the Use of Military Force,” International Studies Quarterly, Vol. 36, pp. 49-74; Gelpi, Feaver, and 

Reifler, Paying the Human Costs of War.

36. Gelpi, Feaver, and Reifler, Paying the Human Costs of War.

37. Full results of these models are reported in the online appendix available from www.jamesigoewalsh.com. The estimation 

technique is ordinary least squares regression. Ordered logistic 

regression produces substantively similar results. See the online data and code for details. We also included two measures of 

general attitudes towards the use of force as independent variables—militant assertiveness and isolationism (drawn from Richard K. Herrmann, Philip E. Tetlock, and Penny S. Visser, “Mass 

Public Decisions on Go to War: A Cognitive-Interactionist Framework,” American Political Science ReviewI, Vol. 93 No. 3, 1999, pp. 

553-573). Including these independent variables did not alter 

the substantive size or statistical significance of the variables for 

drone strikes. 

38. Pamela Johnston Conover and Virginia Sapiro. “Gender, 

Feminist Consciousness, and War,” American Journal of Political 

Science, Vol. 37, 1993, pp. 1079-1099.

39. Note that in our experiment, gender does not influence 

attitudes towards the use of force for humanitarian intervention 

(see Figure 8). This is consistent with earlier works which find 
47

that women are as or more likely to support military action in 

such cases. See Deborah Jordan Brooks and Benjamin A. Valentino, “A War of One’s Own: Understanding the Gender Gap 

in Support for War,” Public Opinion Quarterly, Vol. 75, No. 2, 

2011, pp. 270-286.

40. E.g., Peter Hays Gries, The Politics of American Foreign 

Policy: How Ideology Divides Liberals and Conservatives Over Foreign Affairs, Stanford, CA: Stanford University Press, 2014; 

Richard Johnston, “Party Identification: Unmoved Mover or 

Sum of Preferences?” Annual Review of Political Science, Vol. 9, 

2006, pp. 329-351.

41. Bueno de Mesquita and Siverson, “War and the Survival 

of Political Leaders”; Goemans, “Fighting for Survival”; Rousseau, Thrall, Schulzke, and Sin, “Democratic Leaders and War.”

42. Sauer and Schörnig “Killer Drones: The ‘Silver Bullet’ of 

Democratic Warfare?”

43. Singer, Wired for War.

44. Kreps and Kaag, “The Use of Unmanned Aerial Vehicles 

in Asymmetric Conflict”; Kaag and Kreps, Drone Warfare.

45. Gelpi, Feaver, and Reifler, Paying the Human Costs of War.

46. Jentleson, p. 64.

47. Beauchamp and Savulescu, “Robot Guardians.”

48. Paul Robinson, “Ethics Training and Development in the 

Military,” Parameters, Spring 2007; Chris Case, Bob Underwood, 

and Sean T. Hannah, “Owning Our Army Ethic,” Military Review: 

The Army Ethic, 2010, pp. 3-10; Jeffrey Wilson, “An Ethics Curriculum for an Evolving Army,” Paul Robinson, Nigel De Lee, and 

Don Carrick, eds., Ethics Education in the Military, Burlington, VT: 

Ashgate Publishing, Ltd, 2008.

49. Michael Pasquarett, ed., Perspectives on Embedded Media: Selected Papers from the U.S. Army War College, Carlisle, PA: US Army 

War College, 2004; Major Edward L. English, Towards a More Pro-
48

ductive Military-Media Relationship, Fort Leavenworth, KS: School 

of Advanced Military Studies, U.S. Army Command and General 

Staff College, 2005; Major Chad G. Carroll, “The U.S. Army Public 

Diplomacy Officer: Military Public Affairs Officers” Roles in the 

Global Information Environment,” Master’s Thesis, Chapel Hill, 

NC: University of North Carolina at Chapel Hill, 2007.

50. Richard C. Eichenberg, “Victory Has Many Friends: U.S. 

Public Opinion and the Use of Force,” International Security, Vol. 

30, No. 1, 2005, pp. 140–177; Sarah Kreps, “Flying under the Radar: A Study of Public Attitudes Towards Unmanned Aerial Vehicles,” Research & Politics 2014, available from rap.sagepub.com/

content/1/1/2053168014536533; James Walsh, “Precision Weapons, 

Civilian Casualties, and Support for the Use of Force,” Political 

Psychology, 2015.

51. Kreps and Kaag, “The Use of Unmanned Aerial Vehicles 

in Asymmetric Conflict”; Kaag and Kreps, Drone Warfare.

52. Trevor McCrisken, “Obama's Drone War,” Survival: Global 

Politics and Strategy, Vol. 55, No. 2, 2013, pp. 97-122.

53. John Mueller, “Public Opinion as a Constraint on U.S. 

Foreign Policy: Assessing the Perceived Value of American and 

Foreign Lives,” National Convention of the International Studies Association, 2000; John Tirman, The Deaths of Others: The 

Fate of Civilians in America’s Wars, New York: Oxford University 

Press, 2011.

54. Alexander B. Downes, “Desperate Times, Desperate Measures: The Causes of Civilian Victimization in War,” International 

Security, Vol. 30, No. 4, 2006, pp. 152-195; Alexander B. Downes, 

“Restraint or Propellant? Democracy and Civilian Fatalities in 

Interstate Wars,” The Journal of Conflict Resolution, Vol. 51, No. 

6, 2007, pp. 872-904; Alexander B. Downes, Targeting Civilians in 

War, Ithaca, NY: Cornell University Press, 2008.

55. Kreps, “Flying under the Radar.”

56. Walsh, “Precision Weapons, Civilian Casualties, and 

Support for the Use of Force.”
U.S. ARMY WAR COLLEGE

Major General William E. Rapp

Commandant

*****

STRATEGIC STUDIES INSTITUTE

and

U.S. ARMY WAR COLLEGE PRESS

Director

Professor Douglas C. Lovelace, Jr.

Director of Research

Dr. Steven K. Metz

Authors

Dr. James Igoe Walsh

Dr. Marcus Schulzke 

Editor for Production

Dr. James G. Pierce

Publications Assistant

Ms. Rita A. Rummel

*****

Composition

Mrs. Jennifer E. Nevil