Since the end of the Vietnam War, the United States has refrained from the widespread, intentional targeting of civilian populations in times of war. Public opinion polls seem to reflect a marked decline in American support for targeting foreign civilians since that time. Drawing on original public opinion surveys, as well as other historical material, this essay explores several explanations for these changes. Although there is some evidence that the public's views about the morality of civilian targeting have shifted, I argue that two other explanations also play an important role in the changes in the conduct of American wars. First, a mounting skepticism, especially within the U.S. military, about the efficacy of killing civilians, has undercut the primary motivation to even consider such tactics. Indeed, many U.S. military leaders now perceive that killing adversary civilians in large numbers – intentionally or unintentionally – usually backfires, making the adversary fight harder or driving more civilians to join or support the adversary's forces. Second, due to the lower stakes, and especially the dramatically lower fatality rates suffered by American troops in recent wars, the temptation to attempt to end wars quickly with a “death blow” against adversary cities has become less potent. Under certain conditions, however, a majority of Americans would still support today the kind of population bombing last practiced during World War II.

Nineteen forty-five was the dawn of not only the nuclear era, but also the era of scientific public opinion polling. In September of that year, Roper Opinion Research conducted a nationwide public opinion poll for Fortune magazine on the use of nuclear weapons against Japan one month earlier. The results showed that the majority of the nation (54 percent) agreed that the United States “should have used the two bombs on cities, just as we did.”1 But 14 percent believed that “we should have dropped one first on some unpopulated region, to show the Japanese [the bomb's] power, and only dropped the second one on a city if they hadn't surrendered after the first one.” Only 5 percent of the public felt that “we should not have used any atomic bombs at all,” while 23 percent, however, preferred instead that “we should have quickly used many more of them before Japan had a chance to surrender.”2 This echoed a 1944 poll that asked, “What do you think we should do with Japan as a country?” to which 13 percent of American respondents chose “kill all Japanese.”3 Although racism and the resentment provoked by Pearl Harbor undoubtedly hardened attitudes against the Japanese, there was also virtually no public opposition to the U.S. and British bombing of civilian populations in Germany, which killed nearly as many civilians as were killed by the U.S. bombing of Japan.

Many Americans contemplating these results today will be shaken by the willingness of their fellow citizens to support the intentional killing of hundreds of thousands of civilians. Indeed, when I replicated the 1945 atomic bombing poll in 2012, using nearly identical wording, the results were markedly different.4 Sixty-seven years later, only 30.2 percent of the public agreed that dropping the bombs on Hiroshima and Nagasaki had been the right choice. More than twice as many (29.9 percent) indicated that they would have preferred a demonstration first on an unpopulated region, while more than four times as many people in 2012 (19.8 percent) said that the United States should not have dropped any bombs on Japan. Just 2.5 percent regretted that the United States had not used many more bombs before Japan had the chance to surrender – about one-tenth the proportion who preferred that option in 1945.5

Although the United States' military capability to lay waste to its adversaries' cities has grown exponentially since the end of World War II, the United States has, at least since the end of the Vietnam War, refrained from the widespread, intentional targeting of civilian populations in times of war. In World War II, Korea, and Vietnam, the United States inflicted hundreds of thousands (or more) civilian casualties on its adversaries. A large proportion of these deaths resulted from the intentional targeting of civilian populations. In contrast, in the 1991 Persian Gulf War, the United States killed less than four thousand civilians in military attacks. Approximately five hundred civilians were killed by nato airstrikes in Kosovo in 1999.6 In the Iraq War, the human rights organization Iraq Body Count estimates that U.S. and coalition forces killed approximately fourteen thousand civilians from 2003 to 2011.7 Although the estimated thirty thousand total civilian deaths in Afghanistan have not been systematically attributed to the various parties to the war, a very rough estimate based on un data suggests that U. S., coalition, and “pro-government” Afghan forces probably killed less than six thousand civilians from 2001 to 2014, with approximately half of those deaths caused by coalition airstrikes.8

Deterrence cannot explain America's more humane conduct in recent wars. The United States has maintained this policy of comparative restraint despite the fact that none of the adversaries the United States has engaged with militarily since World War II has possessed the capacity to retaliate in kind. In fact, the U.S. military has gone to considerable lengths in recent decades to minimize the killing of civilians during war, including adopting rules of engagement that increase risks to U.S. troops or choosing weapons that reduce collateral damage but diminish the chances of successfully destroying military targets. In a review of the U.S. military's conduct in the Iraq War, security scholar Colin Kahl has argued that although U.S. military forces killed thousands of Iraqi civilians as collateral damage, the United States had “dramatically reduced the number of civilian casualties relative to what they might otherwise have been in the age of carpet bombing.”9 By Kahl's calculation, even putting aside the important distinction between intentional targeting and collateral deaths, the rate of “Iraqi civilian fatalities attributable to direct U.S. action and crossfire through the end of 2006 were 17 to 30 times lower than those from bombing and shelling alone in Vietnam.”10

What can explain this apparent transformation in U.S. conduct of war and public attitudes toward the use of force? Drawing on public opinion surveys, as well as other historical material, this essay will explore three broad explanations for the change. The first explanation – the one most commonly cited by scholars of the conduct of war – claims that there has been a decisive shift in the norms surrounding the targeting of civilians. By this account, Americans' ideas about what constitutes appropriate and ethical conduct in war have changed for the better. The second explanation points to changing ideas about how to win wars, rather than focusing on changing understandings of the ethics of war. Whereas in World War II, attacking civilian morale or productive capacity through strategic bombing was seen as an effective strategy for coercing surrender, by the end of the Vietnam War, military and civilian elites, and perhaps the public as well, had begun to question the efficacy of intentionally killing civilians. In fact, many had concluded that doing so was largely counterproductive. Lastly, the third explanation focuses instead on the changing nature of the wars that the United States has waged since World War II, especially since Vietnam. According to this explanation, what has changed is not principally U.S. moral character or military strategy, but the pressures that recent wars have placed on Americans to consider targeting civilians. Due to the lower stakes, and especially the dramatically lower fatality rates suffered by American troops in recent wars, the temptation to end wars quickly with a “death blow” against adversary cities has been much less potent.

These three explanations for the shift in American attitudes toward war are not mutually exclusive. Under certain circumstances, however, the different underlying mechanisms identified by each of these explanations may push Americans in divergent directions. Whether the relatively restrained pattern of warfare that the United States has observed for the past forty years will be sustained in the next forty will depend upon the relative strength of these mechanisms.

The most commonly articulated argument for the decline in the intentional targeting of civilian populations by the United States since 1945 focuses on the increasing internalization by Americans of the international norm of noncombatant immunity. Although the principle that civilians deserve at least some protection from the horrors of combat is one of the oldest rules of warfare, many scholars assert that the norm began to spread faster and generate a much higher degree of compliance after World War II and the entry into force of the Fourth Geneva Convention in 1949.11 Airpower expert Ward Thomas, for example, contends that “the bombing norm has slowly recovered from the catastrophe of World War II. While far from absolute, the reborn norm has in recent decades engendered a sensitivity to noncombatant casualties that not only constrains states from targeting civilian populations per se but also creates pressures to minimize incidental casualties in general.”12 Political scientist Neta Crawford, on the other hand, argues that Vietnam “constitutes a turning point in U.S. policy …. After Vietnam, declaratory policy and operational planning increasingly emphasized protecting civilians and U.S. authorities instituted methods to mitigate civilian casualties…. To the extent they adopted the principle of civilian immunity, it was part of a global change in views about human rights.”13

Public opinion polls from the seventy years after World War II provide mixed support for this view. Very few polls have asked Americans to reflect explicitly on the targeting of civilians in war, but those that do generally indicate a decrease in Americans' willingness to violate noncombatant immunity compared to attitudes during World War II. Surprisingly large numbers of Americans, however, continue to express support for attacks that would kill large numbers of civilians. A 1968 Gallup Poll, for example, asked Americans if they would favor or oppose a plan that would “stop all bombing of North Vietnam but with the understanding that if after one or two months the North Vietnamese do not begin to remove their soldiers from South Vietnam that the U.S. would then decide whether to bomb all of North Vietnam including the cities.” Forty-eight percent favored the plan and 39 percent opposed it.14 Three years later, prompted by the courts martial of fourteen American officers involved in the infamous My Lai massacre, a Harris poll asked subjects to “suppose you were a soldier in Vietnam” and “were ordered to shoot old men, women, and children in a village where the civilians were suspected of aiding the enemy.”15 A slight plurality of respondents (43 percent) said it would be more right to follow orders, but nearly as many (41 percent) said it would be better to refuse.16

By the end of the war, however, attitudes seem to have shifted further in favor of protecting civilians. A January 1973 Harris poll, which asked Americans about the heavy “linebacker” bombing raids on North Vietnam, found that a majority (51 percent) opposed the bombing, while 37 percent supported it, and a plurality (46 to 31 percent) acknowledged that “it was inhuman and immoral for the U.S. to have bombed Hanoi's civilian centers the way we did.”17 Nevertheless, the public also agreed overwhelmingly (71 percent to 16 percent) that “what we did in bombing Hanoi was no worse than what the Communists have done in the Vietnam War.” The Harris Survey concluded that “the American people have an uncomfortable sense about the bombings, and would rather have preferred another way to bring North Vietnam back to the negotiating table to end the war. Nevertheless, their reaction was somewhat less than total indignation and on some dimensions they are prepared to justify the bombings as the final stroke to end a cruel and unhappy war.”18

Public opinion polls in the United States' more recent wars suggest a similar ambivalence toward civilian casualties. In the Persian Gulf War, for example, a poll sponsored by The Washington Post asked Americans whether “United States bombers should pass up some possible military targets if Iraqi civilians might be killed in the attack, or not?”19 The public opposed avoiding such targets by a margin of almost two-to-one.20 In mid-February 1991, approximately one month after the bombing campaign against Iraq had begun, Gallup asked Americans to consider the following choices: “Some people say that President Bush should continue the air war for at least several more weeks to make a ground war unnecessary or as easy as possible for allied forces. Others say the President should start the ground war sooner because the air war is doing too much damage to Iraq and its civilians – damaging our position in the Arab world.” Of the respondents, 87 percent said they preferred to continue the air war, with only 8 percent in favor of starting the ground war as soon as possible.21

In 2006, following on reports of the Haditha killings by U.S. troops in Iraq, a poll sponsored by The Los Angeles Times reminded Americans of recent “reports that American troops in Iraq may have killed unarmed Iraqi civilians during military operations” and asked whether that changed their “feelings about the war in Iraq in any way.”22 Sixty-six percent of respondents said that the news did not change their views of the war, while only 23 percent said they had become less supportive.23

In 1999, to mark the fiftieth anniversary of the Geneva Convention, the International Committee of the Red Cross sponsored a major international survey on attitudes about the laws of war.24 Evidence that the American public had internalized international norms against the killing of civilians in war remained mixed. When asked about the appropriate behavior of military forces when soldiers “attack to weaken the enemy,” only 4 percent of Americans said combatants should be free to attack “combatants and civilians.” However, 42 percent said soldiers should “attack enemy combatants and avoid civilians as much as possible,” and 52 percent said they should “attack only enemy combatants and leave civilians alone.”25 In a separate poll, also conducted in 1999, Americans were asked if they “had to make a decision about using the American military,” how important each item on a list of several factors would be: 79 percent of Americans said that the “number of civilians who might be killed” would be an important factor in deciding whether or not to use force, second only to the 86 percent who chose the “number of American lives that might be lost.”26

The Red Cross survey also revealed, however, that one-third of Americans had never heard of the Geneva Convention and only 21 percent believed that there were any laws that regulated “attacking enemy combatants in populated villages or towns in order to weaken the enemy, knowing that many women and children would be killed.”27 Of those polled, 29 percent said it would be “okay to attack” civilians who voluntarily gave food and shelter to enemy combatants in times of war.28 These attitudes appear to have remained relatively stable in the last fifteen years. In a similarly worded poll conducted in 2014, Scott Sagan and I asked respondents whether “foreign civilians who sympathize politically with U.S. adversaries are fair targets in times of war, even if the civilians do not take up arms themselves.”29 Thirty-eight percent of the public agreed they were. Support for targeting civilians rose to 51 percent when subjects were told that the civilians had “provided food and shelter to adversary soldiers.”

Taken together, these results do seem to suggest that the American public has become more accepting of the principle of noncombatant immunity than it was at the end of World War II. But significant segments of the public continue to support attacks that would seem to violate the norms of distinction and proportionality, especially when doing so offers the possibility of reducing the risks to American soldiers.

The second explanation for the apparent shift in American attitudes and conduct in war focuses not on changing views about the ethics or legality of killing civilians, but rather on changing views about the efficacy of doing so. For much of human history, armies have considered deliberate attacks against civilian populations a powerful weapon of war – a way of coercing surrender or depriving the adversary of the weapons, supplies, and recruits that civilian populations produce. Beginning with the theories of airpower advocates like Giulio Douhet and later Hugh Trenchard and Curtis LeMay, this logic was formalized into the operational doctrine that guided much of the allied bombing campaigns in World War ii, as well as subsequent bombing campaigns in Korea and Vietnam. These doctrines explicitly rejected conventional distinctions between combatants and civilians in favor of a concept of total war that rendered almost anyone on the adversary's side a legitimate target. As LeMay put it, “There are no innocent civilians. It is their government and you are fighting a people, you are not trying to fight an armed force anymore. So it doesn't bother me so much to be killing the so-called innocent bystanders.”30

From the start, some military thinkers questioned the wisdom of diverting resources away from the front lines toward the strategic bombing of enemy cities, and some questioned whether doing so would only stiffen the adversary's resolve. General Carl Spaatz, the commander of Allied Strategic Air Forces in Europe during World War II, opposed the British policy of nighttime area bombing in favor of daylight “precision” attacks on strategic industry and military targets. Spaatz, however, later explained that “it wasn't for religious or moral reasons that I didn't go along with urban area bombing,” but rather because he believed that precision bombing “could win the war more quickly.”31 Indeed, as Spaatz understood, U.S. bombing raids in Germany, often conducted through overcast skies, were anything but precise and resulted in tens of thousands of civilian deaths.32 From World War II through the end of the Vietnam War, however, proponents of population bombing continued to influence the American practice of war. Public views on the efficacy of targeting civilians during this period are harder to gauge with precision, but the few polls available seem to indicate that the public largely accepted that bombing the adversary's population centers, whether it was ethical or not, was an effective tool in times of war.

During World War II, few Americans seemed to question the efficacy of strategic bombing. In 1945, only 8 percent of the public believed that the atomic bombings had not shortened the war with Japan to some extent, and 53 percent felt the bomb had shortened the war by at least six months.33 One year earlier, 47 percent agreed that the Allied bombing of Germany had decreased the fighting spirit of the German people, while only 26 percent were worried that the bombing had increased German resistance.34

These attitudes persisted at least through the Vietnam War. A September 1972 Harris poll, for example, found that the public agreed 53 to 32 percent that “by mining harbors and bombing, the North Vietnamese will come to peace terms faster.”35 In January 1973, another Harris poll showed that Americans agreed 48 to 33 percent with the statement: “The only language Hanoi will listen to is force, such as bombing their cities.”36 The majority of the public seemed to dismiss the idea that the bombing would simply make the North Vietnamese fight harder. In January 1967, when asked whether American bombings were likely to “unite the people of North Vietnam,” 51 percent of Americans disagreed and only 25 percent agreed.37 The same poll found that 49 percent agreed that the bombings would “bring North Vietnam to negotiations,” while only 23 percent disagreed.38

After Vietnam, however, attitudes within the American military about the effectiveness of targeting civilian populations appear to have changed dramatically. Not only did post-Vietnam military leaders cease to advocate for the bombing of enemy population centers, they frequently argued that minimizing civilian casualties was critical to success. In the First Gulf War, for example, military planners expressed concern that civilian casualties could undermine international support for the war effort and issued orders to targeteers that “anything which could be considered as terror attacks or attacks on the Iraqi people will be avoided.”39 No doubt the change in strategy was facilitated, at least in part, by the development of much more accurate, precision-guided weapons systems – unavailable to commanders in previous wars – that made it possible to strike military targets in populated areas without targeting an entire village or city.

In recent years, the consensus of American military thinking about the efficacy of targeting civilians has continued to evolve in favor of minimizing noncombatant casualties, even in ground warfare. This trend has been driven in part by the military's increased focus on counterinsurgency wars that, unlike conventional warfare, place a premium on maintaining a cooperative relationship with the adversary's civilian population. Many observers point to the publication of the Army's new counterinsurgency field manual (FM2–14) in 2006 – which emphasized civilian protection and “hearts and minds” as keys to victory – as marking the Army's acceptance of the view that even unintentional noncombatant fatalities could be counterproductive.40 As Joseph Felter and Jacob Shapiro have documented, U.S. commanders in Afghanistan worked actively to convince troops to exercise “courageous restraint” in the use of force, because they believed that protecting Afghan civilians was critical to winning the war.41 In 2009, before taking command of U.S. forces in Afghanistan, General Stanley McChrystal told his Senate confirmation committee that “the measure of effectiveness [in Afghanistan] will not be the number of enemy killed. It will be the number of Afghans shielded from violence.”42 McChrystal's first “tactical directive” to commanders in the field upon taking command further emphasized this point:

Like any insurgency, there is a struggle for the support and will of the population. Gaining and maintaining that support must be our overriding operational imperative…. We must avoid the trap of winning tactical victories – but suffering strategic defeats – by causing civilian casualties or excessive damage and thus alienating the people. While this is also a legal and a moral issue, it is an overarching operational issue – clear-eyed recognition that loss of popular support will be decisive to either side in this struggle.43

Although the evidence of a significant change since Vietnam in professional military thinking about the practical importance of minimizing civilian casualties is strong, public attitudes do not appear to have changed as dramatically. In a 2014 poll, Scott Sagan and I found that 52 percent of the public agreed that “the U.S. would be more likely to win its wars if we didn't care so much about avoiding killing foreign civilians.”44 These findings are also reflected in widespread public support for American drone strikes against suspected terrorists, which have been widely criticized in the press as counterproductive. An October 2013 poll, for example, found that 50 percent of Americans agreed that the use of drones “in countries such as Pakistan, Yemen and Somalia has made the United States safer from terrorism,” while only 14 percent said it had made America less safe.45

Although the first two explanations for the change in U.S. conduct of war since World War II highlight different causes of this transformation, each of them attributes the change to the increasing acceptance of new ideas by the American public or military decision-makers. The third explanation I wish to explore, however, suggests that the most important change has been not in our moral character, but in the character of the wars that the United States has fought, especially since Vietnam. Without exception, these wars have been conducted at comparatively low cost in American lives and have been waged against significantly weaker adversaries over secondary U.S. interests. As a result, the pressures to find ways to end these wars quickly and successfully have been much less powerful and, for the most part, Americans have managed to wage them without even the need to consider directly targeting adversary civilians.

A comparison of monthly military fatality rates in the United States' major wars since World War II helps illustrate this point. The U.S. military fatality rate for the forty-four months the United States was involved in World War II comes to over 9,200 deaths per month. In Korea, the monthly fatality rate dropped to 987, and then to 485 in Vietnam (from 1963 to 1973). Since those wars, however, American military fatality rates have declined even more dramatically. In the First Gulf War, the U.S. military suffered less than one hundred fifty deaths per month – most due to accidents or friendly fire. In Afghanistan, the monthly death rate since 2001 has been fourteen. In the Iraq War, the United States lost an average of forty-eight soldiers per month between 2003 and 2011. Indeed, the United States has lost fewer soldiers in all its wars since Vietnam combined than it did in a single average month of World War II. It is worth noting that these fatality rates do not take into account the increase in the size of the overall American population over this period, which makes American per capita losses even lower in recent wars. If the U.S. population were as large in 1945 as it was in 2015, the monthly death rate in World War II would have been equivalent to over twenty thousand. Even today's much lower death rates have placed a terrible burden on the nation, of course, but the perceived urgency of staunching the bleeding has been considerably less in recent wars. This trend has probably been reinforced by the discontinuation of the draft after Vietnam, which has meant that the costs of the United States' recent wars have been borne exclusively by volunteers.46

Viewed from this perspective, it is perhaps easier to understand why Americans in 1945 might have been more willing to support the bombing of enemy cities, even if some harbored doubts about the morality or efficacy of such a strategy. Of course, it is impossible to know how Americans today would react to a war in which the United States was perceived to be fighting for its existence, and in which each new month of war brought with it ten or twenty thousand additional American deaths.

One way to explore this question, however, is simply to ask Americans to imagine what they would do in the kinds of situations in which the pressures to kill large numbers of foreign civilians might be greater. In one such study, conducted in July 2015, Scott Sagan and I asked Americans to read a fictional news story about a U.S. crisis with Iran. The story was designed to roughly parallel the conflict between the United States and Japan in World War II. In the story, subjects read that a major war had broken out between Iran and the United States after UN inspectors uncovered a covert Iranian nuclear weapons program in clear violation of the Non-Proliferation Treaty and Iran's recent agreement with the United States and other world powers. The United States imposed new economic sanctions on Iran, which prompted Iran to retaliate by sinking a U.S. aircraft carrier in the Persian Gulf, killing over 2,400 sailors (the number killed in Pearl Harbor). The story reported that the United States had then sent ground troops into Iran in an effort to topple the Iranian government. U.S. forces met with heavy fighting and suffered ten thousand fatalities in the first several months of the war. Subjects read that the president was now considering two options to end the war. The first option would continue the ground war, which military leaders estimated would result in the deaths of twenty thousand additional U.S. troops before Iran was defeated. The second option, called the “shock strategy,” would deliberately target the Iranian city of Mashad with a nuclear weapon “in the effort to undermine civilian support for the war and pressure the Iranian government to surrender.” The attack was expected to destroy much of the city and kill one-hundred thousand Iranian civilians. When asked which option they preferred, 56 percent of Americans chose the nuclear strike and 60 percent said they would approve of the strike if the president ordered it. Given the option to conduct the same strike using conventional munitions instead of nuclear bombs, 67 percent of Americans preferred the airstrike.47

Admittedly, we cannot know whether the kinds of attitudes expressed by subjects in a thought experiment like this reflect the way Americans would react to real world crises. Indeed, polls taken before World War II indicate that many Americans might have been shocked to see how much their own attitudes had changed by the end of the war. The interwar period in the United States, it is often forgotten, witnessed an unprecedented flourishing of pacifist and disarmament movements. World leaders, including Winston Churchill and Franklin Roosevelt, had repeatedly condemned the bombing of civilian populations early in the war that, according to Roosevelt in 1939, “sickened the hearts of every civilized man and woman, and has profoundly shocked the conscience of humanity.”48 A poll conducted by Gallup in April of 1938 found that 91 percent of Americans concurred that “all nations should agree not to bomb civilians in cities during wartime” and 61 percent agreed that the United States should convene “a conference of all nations to make such an agreement.”49 Although it is possible that Americans in 1938 answered those questions cynically, never sincerely believing that civilians should be protected during war, it seems more likely that most simply could not imagine what they would be willing to do to bring an end to a war like World War ii. If so, Americans today must ask themselves whether they are any better at imagining how they would behave should we face such desperate times again.

Understanding the causes of the changes in the U.S. conduct of war is critical if we wish to know whether the United States' commitment to a more humane way of war will strengthen or erode in the years ahead and whether other nations will adopt similar restraint. If the United States' increased efforts to protect foreign civilians in recent wars have been driven primarily by a fundamental normative change in the attitudes of the public as well as civilian and military elites, we can expect the trend to continue and to spread. Indeed, international polls suggest that the U.S. public appears to be far more tolerant of inflicting civilian casualties than citizens of most other nations. A 2011 poll conducted by Gallup, for example, found that 49 percent of Americans agreed that it was sometimes justified “for the military to target and kill civilians” – the highest among all 131 countries polled.50 By contrast, only 3 percent of Spaniards and 9 percent of Germans and Japanese agreed. On the other hand, to the extent that U.S. restraint can be explained by the changing nature of the wars we fight, or by changing views about the military effectiveness of targeting civilians, the recent trend seems more tenuous. Should our adversaries or our strategic concepts change, we might revert to old ways. Perhaps even Western European publics would revise their beliefs if their nations were forced to make the kinds of terrible choices about war from which they have largely been spared since 1945.

Understanding the causes of the changes in the United States' conduct of war could also inform the policy choices we make as we endeavor to increase protection for civilians during times of war. If changing public norms about the conduct of war have been responsible for our shift in attitudes and behavior, it follows that we should focus on spreading those norms through educational efforts directed toward the public both at home and abroad. If changing views of military strategy have played a larger role, our efforts should center on educating the military and civilian elites who craft military strategy. If the changing nature of the United States' wars has enabled our more restrained behavior, however, there may be little we can do except to redouble our efforts to avoid such wars in the first place.


Roper/Fortune Survey, September 1945, survey question (Ithaca, N.Y.: Roper Center for Public Opinion Research, 1945), accessed through iPOLL database (USROPER.45-050.R16). This shows a decline in support from one month earlier, in August 1945, within days of the bombings, when a Gallup Poll found that an overwhelming 85 percent of Americans approved and only 10 percent disapproved of the use of the atomic bombs against Japanese cities. See David W. Moore, “Majority Supports Use of Atomic Bomb on Japan in wwii,” Gallup, August 5, 2005,


Roper/Fortune Survey, September 1945. The remaining 6 percent chose “Don't know.”


John Dower, War Without Mercy: Race and Power in the Pacific War (New York: Pantheon Books, 1986), 53–54.


Benjamin Valentino, YouGov survey, April 26 to May 2, 2013,


Ibid.; 17.6 percent chose “Don't know.”


Eric V. Larson and Bogdan Savych, Misfortunes of War: Press and Public Reactions to Civilian Deaths in Wartime (Santa Monica, Calif.: rand Corporation, 2006), 65–66.


Iraq Body Count, “Documented Civilian Deaths from Violence,” Iraq Body Count,


Neta C. Crawford, “War-Related Death, Injury, and Displacement in Afghanistan and Pakistan 2001–2014,” Costs of War (Providence: Watson Institute for International and Public Affairs at Brown University, 2015),


Colin H. Kahl, “In the Crossfire or the Crosshairs? Norms, Civilian Casualties, and U.S. Conduct in Iraq,” International Security 32 (1) (Summer 2007): 45.


Ibid., 15. See also Steven Pinker, The Better Angels of Our Nature: Why Violence Has Declined (New York: Viking, 2011), 266.


Joshua Goldstein, Winning the War on War: The Decline of Armed Conflict World Wide (New York: Dutton, 2011), 227.


Ward Thomas, The Ethics of Destruction: Norms and Force in International Relations (Ithaca, N.Y.: Cornell University Press, 2001), 148.


Neta C. Crawford, “Targeting Civilians and U.S. Strategic Bombing Norms,” in The American Way of Bombing: Changing Ethical and Legal Norms from Flying Fortresses to Drones, ed. Matthew Evangelista and Henry Shue (Ithaca, N.Y.: Cornell University Press, 2014), 64–65. Crawford also suggests that changing views about the efficacy of targeting civilians have played a role in the changing practice of warfare.


The remaining 13 percent expressed “No opinion.” See Gallup Organization, Gallup Poll (AIPO), September 1968, survey question (Ithaca, N.Y.: Roper Center for Public Opinion Research, 1968), accessed through iPOLL database (USGALLUP.68–767.R19).


Louis Harris & Associates, Harris Survey, February 1971, survey question (Ithaca, N.Y.: Roper Center for Public Opinion Research, 1971), accessed through iPOLL database (USHARRIS.71FEB.R18).


Ibid. The remaining 16 percent chose “Not sure.”


Louis Harris, “Though Opposed to Bombings of Hanoi Most Felt They Spurred Negotiations,” The Harris Survey, February 1, 1973.




ABC News/The Washington Post Poll, February 1991 (Ithaca, N.Y.: Roper Center for Public Opinion Research, 1991), accessed through iPOLL database (USABCWP.442.R06).


Ibid. Of the respondents, 60 percent opposed, 34 percent approved, and 5 percent chose “Don't know/No opinion.”


The remaining 5 percent chose “Don't know.” See Gallup/Newsweek Poll, February 1991, survey question (Ithaca, N.Y.: Roper Center for Public Opinion Research, 1991), accessed through iPOLL database (USGALNEW.105138.R06).


The Los Angeles Times/Bloomberg Poll, June 2006, survey question (Ithaca, N.Y.: Roper Center for Public Opinion Research, 2006), accessed through iPOLL database (USLAT.062906.R55).


Ibid. Of the respondents, 12 percent replied that the news made them “Much less supportive,” in addition to the 11 percent who replied “Somewhat less supportive.” A total of 6 percent said the news made them more supportive (3 percent replied “Much more supportive” and 3 percent replied “Somewhat more supportive”).


Greenberg Research, Inc., The People on War Report (Geneva: The International Committee of the Red Cross, 1999),


Ibid., 60.


Americans Talk Security #9 poll, September 7–18, 1999, quoted in Larson and Savych, Misfortunes of War, 4.


Greenberg Research, Inc., The People on War Report, 70.


Ibid., 63.


Result of an original poll by Scott Sagan and Benjamin Valentino, conducted in 2014. The poll, administered by YouGov from August 5–8, 2014, polled 4,050 American citizens.


Quoted in Michael Sherry, The Rise of American Air Power: The Creation of Armageddon (New Haven, Conn.: Yale University Press, 1989), 287.


Quoted in ibid., 249.


Richard Davis, Carl A. Spaatz and the Air War in Europe (Washington, D.C.: Center for Air Force History, 1993), 435.


Roper/Fortune Survey, September 1945, survey question (Ithaca, N.Y.: Roper Center for Public Opinion Research, 1945), accessed through iPOLL database (USROPER.45-050.R15).


Additionally, 14 percent said it “Made no difference” and 13 percent expressed “No opinion.” See Office of Public Opinion Research Roosevelt Survey, April 1944, survey question (Ithaca, N.Y.: Roper Center for Public Opinion Research), accessed through iPOLL database (USOPOR.44-024.Q02).


Louis Harris, “Heavy U.S. Bombings of N. Vietnam Favored By Majority,” The Harris Survey, September 11, 1972.


Louis Harris, “Though Opposed to Bombings of Hanoi, Most Felt They Spurred Negotiations,” The Harris Survey, February 1, 1973.


The remaining 24 percent chose “Not sure.” See Louis Harris & Associates, Harris Survey, January 1967, survey question (Ithaca, N.Y.: Roper Center for Public Opinion Research), accessed through iPOLL database (USHARRIS.021267.R1A).


Louis Harris & Associates, Harris Survey, January 1967, survey question (Ithaca, N.Y.: Roper Center for Public Opinion Research), accessed through iPOLL database (USHARRIS.021267.R1E).


Quoted in Thomas A. Keany and Eliot A. Cohen, Gulf War Air Power Survey, vol. 1 (Washington, D.C.: U.S. Air Force, 1993), 46. See also Ward Thomas, The Ethics of Destruction: Norms and Force in International Relations (Ithaca, N.Y.: Cornell University Press, 2001), 159–160.


The “All Hands” letter from Major General James Mattis, on the other hand, indicates that the decision to limit civilian casualties may also have been driven by the military's desire to preserve its self-image as warriors fighting with “chivalry to the innocent.” See James Mattis, “A Letter to All Hands,” Leatherneck Forum, March 23, 2004,


Joseph H. Felter and Jacob N. Shapiro, “Limiting Civilian Casualties as Part of a Winning Strategy: The Case of Courageous Restraint,” Dædalus 146 (1) (forthcoming winter 2017).


Thom Shanker, “A New Afghanistan Commander Rethinks How to Measure Success,” The New York Times, June 19, 2009,


Stanley McChrystal, “Tactile Directive,” North Atlantic Treaty Organization (Kabul: Headquarters International Security Assistance Force, July 6, 2009),


Forty-eight percent disagreed. Original poll conducted by Scott Sagan and Benjamin Valentino in 2014.


Of the remaining respondents, 27 percent said it made no difference and 9 percent did not know or refused to answer. See Pew Research Center for the People & the Press/Council on Foreign Relations, “America's Place in the World Survey,” October 2013, survey question, (Ithaca, N.Y.: Roper Center for Public Opinion Research, 2013), accessed through iPOLL database (USPSRA.120313.R59CF2).


See Andrew J. Bacevich, “Whose Army?” Dædalus 140 (3) (Summer 2011): 122–134.


Result of an original poll conducted by Scott Sagan and Benjamin Valentino. The poll, administered by YouGov from July 23–30, 2015, polled 160 American citizens.


Conrad C. Crane, Bombs, Cities and Civilians (Lawrence: University Press of Kansas, 1993), 32.


Gallup Poll, April 1938, survey question (Ithaca, N.Y.: Roper Center for Public Opinion Research, 1938), accessed through iPOLL database (USGALLUP.041538.RA05A and USGALLUP.041538.RA05B).


Gallup Organization, “Views of Violence,”

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license, which permits copying and redistributing the material in any medium or format for noncommercial purposes only. For a full description of the license, please visit