We thank Michael Walzer, Jeff McMahan, and Robert O. Keohane for their thoughtful commentaries on our article in this Ethics & International Affairs symposium. Our article was shaped by their ideas and methods, and their contributions here will deepen readers' understandings of just war doctrine and its application. This rejoinder will focus primarily on points of disagreement. We will also, however, elaborate on the rich research agenda that their commentaries inspire.
Ethics, Rights, and Responsibilities
Walzer and McMahan begin by challenging the language of one of our central survey questions: Do you think the soldiers “acted ethically?” Walzer argues that ethically “is not quite the right word” (p. 446)Footnote 1 and believes we should have asked about soldiers’ rights instead. McMahan argues that it is “misleading” to ask whether soldiers fighting in an unjust war “act[ed] ethically” (p. 452) because excusing conditions, such as duress, could wholly or partially reduce soldiers’ moral responsibility for killing enemy combatants.
We believe, however, that it is appropriate, indeed necessary, to ask respondents if they think the soldiers fighting on an unjust side acted ethically when assessing whether or not they believe in “the moral equality of combatants.” Whether a soldier fighting for an unjust side behaves morally or ethically is the heart of this debate. Elsewhere, Walzer has written that regardless of the justice of the cause of the war, “the moral status of individual soldiers on both sides is very much the same” and claims that German field marshal Erwin Rommel “fought a bad war well, not only militarily but also morally.”Footnote 2 McMahan has written that “it is morally wrong to fight in a war that is unjust because it lacks a just cause.”Footnote 3 By asking whether the soldiers on both sides “acted ethically,” we are therefore clearly testing whether the public agrees more with Walzer or McMahan on this core issue.
McMahan is correct, however, that our findings on punishment do reflect a lower willingness among our subjects to imprison, and especially to execute, conscripts fighting in an unjust war than to imprison or execute volunteers fighting in such a war. This shows that some subjects do recognize duress as a mitigating condition. Still, more than half of subjects who said the conscripts fighting in an unjust war were unethical also felt those soldiers deserved to be imprisoned, suggesting that most did not believe these soldiers were excused or acting within their rights. Future research could usefully focus on a broader set of potential mitigating circumstances.
Keohane, in contrast, challenges the logic of one of our central findings, arguing that it would make “no logical sense” for the public to accept the “stronger revisionist claim” about soldiers’ responsibilities for the justice of the war but then accept the “weaker moral claim about soldiers’ responsibility to avoid committing war crimes” (p. 467). What Keohane has missed here is that while revisionists do argue that soldiers who fight on the unjust side have more responsibility for the cause of the war, many simultaneously give more rights to the soldiers fighting on the just side to kill noncombatants under certain conditions. In his commentary, for example, McMahan argues that it would be just to kill a foreign civilian scientist who would otherwise provide a demonic leader with a weapon of mass destruction. In Killing in War, he argues that Palestinians may have a moral right to kill Israeli civilian settlers (except for children) in the West Bank.Footnote 4 McMahan elsewhere maintains that soldiers fighting on a just side have the moral right to kill prisoners who had fought on the unjust side if holding them or releasing them would endanger the lives of the “just” soldiers still in enemy territory.Footnote 5 Helen Frowe, another prominent revisionist, has gone even further, arguing that many noncombatants who are knowingly engaged in “producing military equipment, designing or testing weapons, building military vehicles, or supplying other materials (including food and medical supplies) used to facilitate the military campaign” of an unjust war are liable to be killed if they can be identified with certainty, their deaths will contribute to winning the war, and disproportionate collateral damage against other civilians can be avoided.Footnote 6 In short, the logic of revisionism weakens noncombatant immunity even among philosophers. Significant numbers of our respondents follow that logic; they just slide further down that slippery slope than either McMahan or Frowe would approve.
Relevance and Reciprocity
Walzer and McMahan both usefully recommend that social scientists ground experiments in real-world examples, involving real countries and the kind of ambiguity that often exists about the justice of the causes of a war, rather than relying on abstract hypothetical scenarios, where the justice or injustice of the attacking party is clearly specified, like the ones in our article. We generally agree and have used real-world scenarios in many of our other survey experiments in order to increase external validity and policy relevance.Footnote 7 Indeed, we have already gathered evidence on the public's views about one of the real-world scenarios that Walzer recommends we consider: whether it would be justified for the United States to attack an Iranian city in retaliation for an Iranian attack on U.S. armed forces in the Middle East. Our 2015 survey experiment found that 59 percent of the American public would approve of a U.S. nuclear strike on an Iranian city that killed two million civilians, in response to an Iranian attack on a U.S. ship in the Persian Gulf, in order to coerce the Iranian government to surrender and avoid a land war estimated to kill twenty thousand U.S. soldiers.Footnote 8 Shockingly, 69 percent of those respondents agreed with the statement “Because the Iranian civilians described in the story did not rise up and overthrow the government of Iran, they must bear some responsibility for the fatalities caused by the U.S. strike.”Footnote 9 We personally believe that such a nuclear strike should never be launched. It would be illegal and immoral, violating the just war principles of distinction, proportionality, and precaution enshrined in the Additional Protocols to the Geneva Conventions. The majority of the American public in our experiment, however, thought otherwise.
This Iran experiment did not, however, respond to Walzer's recommendation that we focus on scenarios that might evoke “intuitive reciprocity” (p. 449), because Iran cannot currently retaliate directly against the United States. We agree that future research should study how considerations of reciprocity and precedent setting influence public and elite attitudes about just war doctrine and the laws of armed conflict.Footnote 10
Revenge Is the Dark Side of Reciprocity
McMahan is a rigorous moral philosopher; our respondents are not. He is right to point out how often they appear to be “deeply confused in their beliefs about the ethics of war” (p. 457), holding inconsistent or baffling positions. He is not alone in this view. Scholars of public opinion have struggled to make sense of seemingly inconsistent or illogical public attitudes ever since Philip Converse published his seminal article in 1964 concluding that the majority of Americans lack coherent and consistent political belief systems.Footnote 11 Some of our respondents may be committed pacifists, but many others may have just been cynical or confused. We doubt, however, that many of them were “committed” to their answers, much less to the logical applications to the historical analogies McMahan offers. We also suspect that many respondents who said they agreed with the Thucydides question—“In war, the strong do whatever they can and the weak do whatever they must. Ethics just don't apply” (pp. 431–432)—were not reflecting personal amoralism but rather their belief in what states and soldiers actually do.
Our findings demonstrate, however, that respondents do have moral instincts that include a strong component of vengeance, triggered by Eastland's unjust aggression. A significant body of literature in psychology and anthropology has shown that revenge, or “retaliatory aggression,” is a deeply ingrained human behavioral response to threats and harms.Footnote 12 Moral philosophers might support retribution in a narrow set of cases to promote justice. What we found is that significant parts of the American public support revenge to impose suffering. Retribution is targeted. Revenge often is not. Walzer's golden rule injunction to “do unto others as you would have them to do unto you” (p. 447), exists side by side with the retributive desire to take “an eye for an eye” and a vengeful impulse that “an eye for an eye is never enough.”
Walzer cites a reassuring May 1941 public opinion poll showing that British citizens who were directly affected by the Blitz were less likely to support the bombing of German cities. Yet it is sad to note that in July 1941, Churchill aroused hearty applause from the London County Council when he told the members, “If tonight the people of London were asked to cast their vote whether a convention should be entered into to stop the bombing of all cities, the overwhelming majority would cry, ‘No, we will mete out to the Germans the measure, and more than the measure, that they have meted out to us.’ . . . You do your worst and we will do our best. Perhaps it may be our turn soon.”Footnote 13
This is one reason why the constraining powers of the laws of armed conflict are needed: to stay the hand of vengeance. Indeed, a central challenge in the world since the September 11, 2001 attacks on the United States has been how best to fight, ethically and legally, against adversaries who do not adhere to the laws of armed conflict and their underlying ethical principles. Walzer may be correct when he writes that just war doctrine does not have constraining power, “like a stop sign on the road” (p. 450). But the laws of armed conflict, based in part on just war doctrine, can provide such stop signs. And regarding decisions about the deliberate killing of noncombatants, we should want those stop signs to be big, bright, and bold.
Let us give an example. In June 2005, a Navy SEAL team in the mountains of Afghanistan was preparing to attack a Taliban leadership target in the valley below when it encountered an unarmed Afghan man in a turban, a farmer, and a teenage boy. The soldiers debated whether to kill the prisoners, fearing that if they released them, they might go back to the village and alert the Taliban of the impending raid. In this case, the constraining power of law coupled with the power of moral intuition led one member of the SEAL team, Marcus Luttrell, to advocate for the release of the prisoners. According to an interview with the Washington Post: “Part of his calculus was practical. ‘I didn't want to go to jail.’ Ultimately, the core of his decision was moral. ‘A frogman has two personalities. The military guy in me wanted to kill them,’ he recalled. And yet: ‘They just seemed like—people. I'm not a murderer.’”Footnote 14
Range and Replication
Keohane is correct to call for the replication of our experiment in the future, since who is president, or what wars are happening in the real world, can influence respondents’ answers even regarding hypothetical scenarios. He also offers many useful recommendations for comparative research to determine whether American views about justice in war are similar to or different from those of citizens in other countries and whether democracies and autocracies differ in systematic ways. Fortunately, some important comparative polling work and social science scholarship exists regarding torture, public vengeance, violations of noncombatant immunity, and different cultures’ normative restrictions on war.Footnote 15
But much more work clearly needs to be done, especially in an era in which the president of the United States is praising and considering pardoning soldiers convicted of war crimes.Footnote 16 We are grateful for the opportunity to contribute to what we believe is an overdue dialogue between empirical scholars of international relations and philosophers of the ethics of war. We hope this dialogue will be the first of many. It is our hope that this symposium will encourage more empirical political scientists, as well as lawyers, psychologists, and historians, to join debates with philosophers and political theorists about the application of just war doctrine.
Just war is too important to be left to the just war theorists.
