Skip to main content Accessibility help
Hostname: page-component-cf9d5c678-9z9qw Total loading time: 0.692 Render date: 2021-07-26T20:33:43.734Z Has data issue: false Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "metricsAbstractViews": false, "figures": true, "newCiteModal": false, "newCitedByModal": true, "newEcommerce": true, "newUsageEvents": true }

Battlefield Mercy: Unpacking the Nature and Significance of Supererogation in War

Published online by Cambridge University Press:  06 September 2019

Rights & Permissions[Opens in a new window]


Debates over how best to ensure appropriate conduct in battle typically draw a binary distinction between rule compliance and rule violation. This framing is problematic, excluding a critical third element of battlefield conduct, supererogation—that is, positive acts that go beyond what is demanded by the explicit rules of war. This article investigates this moral category of action; specifically, situations in which combatants refrain from taking the life of an enemy despite their moral and legal license to do so. It first considers the moral tension between the duty of combatants to kill and battlefield mercy, and goes on to explore the factors that motivate the latter. The article then shifts to consider the significance of supererogation to the ongoing efforts to moderate the conduct of contemporary war. As the article illustrates, supererogatory restraint is constituted by values that when cultivated also incentivize adherence to the more explicit rules and standards of the battlefield. This is demonstrated through analysis of the conduct of Western special forces. The concept of supererogation is of further use when evaluating the origins and implications of “moral injury.” This is verified empirically in the context of armed unmanned aerial vehicles.

Copyright © Carnegie Council for Ethics in International Affairs 2019 

General William T. Sherman was only half-correct when in the midst of the American Civil War he wrote, “War is cruelty, and you cannot refine it.”Footnote 1 War is indeed a brutal and destructive enterprise, the cost of which is most frequently borne by those least deserving. Yet for all its cruelty, war has been and continues to be subject to revision and moderation, both morally through the just war tradition and legally through international humanitarian law. This is an incremental process, with debates ongoing over how best to ensure that belligerents operate in accordance with these moral and legal standards.Footnote 2 These contemporary debates typically draw a binary distinction between rule compliance and rule violation: how can we incentivize the former and prevent and punish the latter?

I argue that this framing is problematic, excluding a critical third category of battlefield conduct: supererogation—positive acts that go beyond what is demanded by the moral and legal rules of war. We rightly focus on the troubling frequency with which combatants, motivated by exigency or animus, disregard behavioral constraints in battle. Too often, however, this same analysis overlooks the opposite phenomenon: situations in which combatants go beyond their moral and legal duties to extend additional protections to the enemy. This omission has left us with an impoverished understanding of the factors that motivate both positive and negative conduct on the contemporary battlefield.

This article seeks to remedy this gap in the research by looking more closely at the nature and significance of supererogation in war. It focuses specifically on supererogatory restraint—that is, the refusal of combatants to take the life of the enemy on humanitarian grounds despite being morally and legally entitled to do so. As the first section outlines, this kind of restraint defies simple moral categorization. Combatants who exercise battlefield mercy exceed their moral and legal obligation to the enemy. In doing so, however, they may be in violation of other responsibilities, including their duty to kill. After highlighting this complexity, the article considers the factors that commonly motivate intercombatant restraint: target vulnerability, empathy, and self-reflection.

The article will then detail how our efforts to refine contemporary war can be enhanced through greater consideration of its supererogatory dimensions. Drawing on the example of the Special Operations Forces in the West, I argue that when harnessed, the factors that motivate battlefield mercy also aid in the development of more effective systems of rule compliance. An analysis of supererogation can also enrich our understanding of the concept of “moral injury”—trauma resulting from a dissonance between a combatant's own moral understanding of war and his or her specific conduct during battle. Treatment of this condition needs to better recognize the potential trauma that may result from the failure to do more than is morally required on the battlefield. The need for such reflection will be reinforced in the final section of this article, which evaluates supererogation in relation to the use of armed unmanned aerial vehicles.

The Puzzle of Battlefield Supererogation

“Supererogation” is the technical term for a class of actions that, while morally good, are not necessarily morally required. To engage in supererogation is to go beyond one's moral duty. The term can describe the relatively mundane, including minor acts of generosity, gift giving, and volunteering, as well as day-to-day forbearance and forgiveness.Footnote 3 It may also include more extreme behavior, including heroic self-sacrifice and saintly acts of restraint and charity.

The origins of the concept can be traced back to Catholic theology, specifically the theological disputes of the sixteenth century. Works of supererogation, understood as meritorious nonduties, were a central component of the Catholic institution of indulgences. J. O. Urmson's seminal 1958 essay “Saints and Heroes” stands as the most important contemporary contribution to the subject of supererogation within ethical theory. Urmson challenged the traditional, and what he regarded as overly restrictive, division of moral action into the obligatory, the permitted (or morally neutral), and the prohibited:

We need to discover some theory that will allow for both absolute duties, which, in Mill's phrase, can be exacted from a man like a debt, to omit which is to do wrong and to deserve censure, and which may be embodied in formal rules or principles, and also for a range of actions which are of moral value and which an agent may feel called upon to perform, but which cannot be demanded and whose omission cannot be called wrongdoing.Footnote 4

One way in which supererogation can manifest in war is through battlefield mercy, which is when combatants refrain from taking the life of an enemy, despite their moral and legal license to do so. Consider the example of Italian lieutenant Emilio Lussu from the First World War. Accompanied by his corporal, Lussu traveled during the night into a position from which he could strike at opposing Austrian forces. Just as he was about to kill a young officer, the would-be target lit a cigarette, a gesture that gave Lussu pause: “This cigarette formed an invisible link between us. No sooner did I see its smoke than I wanted a cigarette myself.”Footnote 5 According to Michael Walzer, who explores the Lussu example alongside similar cases in Just and Unjust Wars, mercy of this type, while commendable, is not obligatory in war, and may therefore “be likened to supererogatory acts.”Footnote 6

Intercombatant restraint is a particularly interesting example of supererogation in that it defies straightforward normative demarcation. It is a dispensation of mercy beyond one's duty to the enemy. At the same time, however, the act itself may be in violation of other moral and legal duties imposed upon the combatant, including the duty to injure and kill the enemy whenever possible. In order to appreciate this tension, we need to first recognize the degree of permissiveness with which intercombatant violence may be exercised on the battlefield. The rules of war place few restrictions on the type and degree of harm that may be directed against opposing fighters. “As far as ordinary combatants are concerned,” notes Yoram Dinstein, “they can be attacked (and killed) wherever they are, in and out of uniform, even when they are not on active duty. There is no prohibition either of opening fire on retreating troops (who have not surrendered) or of targeting individual combatants.”Footnote 7 Immunity from lethal targeting is only restored to combatants who have formally surrendered or to those who are wounded or otherwise incapacitated to the point that they are incapable of defending themselves (hors de combat). Beyond these narrow exceptions, enemy combatants are subject to attack at all times.

The delivery of violence on the battlefield is a right held by all participants in war. It is also, crucially, an obligation. In the United Kingdom, the Military Covenant emphasizes that soldiers have a “legal right and duty to fight and if necessary kill.”Footnote 8 According to Article 99(8) of the Uniform Code of Military Justice, which is part of the United States Code, a combatant who “willfully fails to do his utmost to encounter, engage, capture, or destroy any enemy troops” may be “punished by death.”Footnote 9

In order to engage in intercombatant restraint, soldiers may be required to violate their prima facie duty, grounded in their oath of enlistment, to take enemy life. The transgressive nature of this act is not lost on those who exercise it. As noted above, Emilio Lussu opted to spare the life of the Austrian officer he encountered on the battlefield, but not before acknowledging that “I knew it was my duty to fire.”Footnote 10 The obvious question this raises is whether we can even categorize such behavior as supererogatory. Can we ascribe moral value to an action that exceeds one moral duty while appearing to violate another?

There are some who answer no; an action cannot qualify as supererogatory if the agent must disregard an obligation in order to carry it out.Footnote 11 If we accept this answer, then battlefield mercy is not meritorious, at least when extended to enemy combatants, and thus ineligible for consideration as a supererogatory act. Frances Kamm, however, is among those who reject this logic, arguing that it is possible in specific situations to perform “a supererogatory act and as a foreseen consequence [permissibly] fail to do our duty.”Footnote 12 Kamm substantiates this claim by asking the reader to imagine an individual who, on her way to a lunch appointment, encounters a car crash. In an act of supreme (and nonobligatory) generosity, she offers to donate one of her kidneys to the victim. In doing so, however, she fails to uphold her duty to keep her lunch appointment.Footnote 13 We may rightly regard such conduct as supererogatory, Kamm argues, despite the foreseen transgression of duty that it entails. If we accept that supererogation can coexist with the permissible transgression of duty, then the next question is under what conditions, if any, intercombatant restraint meets this standard.

Mercy in general is a philosophically problematic virtue, given its frequent conflict with the principle of equal justice.Footnote 14 Mercy in war is especially contentious, given the life-or-death stakes involved. In order for battlefield mercy to qualify as supererogatory, the moral worth of the act, sparing the life of the enemy, must outweigh the moral worth of the violated duty, killing the enemy. I argue that this is possible, but only when the target poses no immediate physical threat.

Recall that supererogatory acts are meritorious nonduties. Combatants are not morally obligated to spare the life of the enemy, even those who pose no material threat when targeted.Footnote 15 They may nevertheless feel profound moral discomfort when they injure and kill opposing fighters in moments of acute vulnerability.Footnote 16 Such discomfort was evident during the so-called Highway of Death incident of the first Gulf War, in which retreating Iraqi military personnel were subjected to ten hours of bombardment by Western forces, whose own vulnerability was virtually nonexistent. Four hundred Iraqi fighters were eventually killed, with no loss of coalition life.Footnote 17 While most observers accepted that the attack was legal according to the permissive rules of war,Footnote 18 many were left troubled by what they regarded as an unnecessary and excessive use of violence.

Compare this to another encounter from the Gulf War, in which British army helicopter pilots “circle[d] over . . . [Iraqi] tanks as a warning to the crews, who could escape before the tanks were destroyed.”Footnote 19 According to one of the pilots, the rationale for this was so that “we could feel at peace with ourselves. We had total superiority, but we didn't use it.”Footnote 20 Most observers would regard the mercy displayed by these pilots as morally praiseworthy, despite its necessary tension with the duty to kill. Rules, even those we respect, are imperfect, often failing to properly reflect the principle that underpins them. In situations such as these, when an otherwise just rule produces what many would regard as an unjustly harsh outcome, mercy can function as a form of redress. Meritorious mercy—mercy worthy of praise rather than condemnation—is applied in response to a situation where “the application of the rules leads to a sentence more severe than that which justice, independent of the operative rules, would require.”Footnote 21

Battlefield mercy follows the same logic. When the rules governing intercombatant violence are overinclusive and expose nonthreatening enemies to unnecessary or excessive harm, mercy can alleviate the resulting tension with our moral intuition. Under such conditions, killing remains a right but loses its urgency as a moral obligation. To be clear, refraining from killing the enemy is not merely supererogatory but obligatory when the enemy has either surrendered or been rendered hors de combat. Likewise, such restraint is unjust when the enemy poses an imminent and significant physical danger on the battlefield. Supererogatory mercy lies between these two extremes. It is exercised in the service of vulnerable opponents, but, critically, only those whose vulnerability falls short of the degree necessary to invalidate their moral and legal liability to direct and deliberate harm.

This is not intended to stand as a definitive moral determination. The ethical standards of war have always been, and remain, highly contested, a reality that complicates our ability to allocate particular acts in battle to the category of supererogation. A pacifist, for instance, might argue that battlefield mercy is always obligatory, rather than supererogatory, regardless of the bellicosity of the potential target. We would also likely find contestation from within the just war tradition itself regarding the parameters of supererogation. Just war “revisionists” dispute the long-standing notion of a “moral equality” between opposing combatants, arguing instead that the justice of a fighter's cause is central to the permissibility of their use of force. This reformulation dispossesses “unjust” combatants of their moral right to kill. By this logic, were an unjust fighter to refrain from killing his or her just opponent, the action would not be supererogatory, but rather an abstention from a morally proscribed act.

Others might reject supererogation on more realist grounds. Francis Lieber, author of the 1863 document that later came to be known as the Lieber Code—the first modern codification of the laws of war—wrote that “it is my duty to injure my enemy . . . the most seriously I can, in order to obtain my end . . . if destruction of the enemy is my object, it is not only my right, but my duty, to resort to the most destructive means.”Footnote 22

According to this perspective, battlefield mercy is a vice, directly at odds with the duty of all combatants to degrade the capabilities of the enemy and win the war. Supererogatory restraint may also be objected to on the basis that vulnerable adversaries rarely remain vulnerable for long. The decision to spare temporarily unoffending opponents has to be weighed against the potential of these same individuals to pose a mortal threat to others at a later time.Footnote 23 The intention of this article is not to settle the long-standing debate over the reach and limits of battlefield violence. It is merely to highlight the philosophical coherency of supererogatory restraint in battle within the context of the existing rules of war.

The next section will explore the factors, beyond enemy vulnerability, that motivate battlefield mercy.

The Motivation for Battlefield Supererogation

Target vulnerability is an essential precondition of supererogatory restraint in battle. It is not, however, the sole incentive for such conduct. Empathy for “the other” and moral self-reflection are also important motivators for intercombatant mercy.


Empathy can be understood as the capacity to recognize and respond to the distinct affective experiences of another individual.Footnote 24 It arises when we “mentally transpose” ourselves to the subject's perspective, to comprehend a situation from his or her point of view.Footnote 25 In war, this may include the enemy, particularly those who face comparable obstacles and adversity. As philosopher and former soldier J. Glenn Gray observed, “The foe is a human being like yourself, the victim of forces above him over which he has no control.”Footnote 26 Empathy, along with its close companion, sympathy—the feeling of compassion, sorrow, or pity for the hardship of another—has long been an important facilitator of reactive altruism in war, including intercombatant mercy.

The power of empathy to induce supererogatory restraint is evidenced in part by the determination of militaries across history to undermine it.Footnote 27 In his memoir of the First World War, Brigadier General F. P. Crozier described his training regime in detail:

I, for my part, do what I can to alter completely the outlook, bearing, and mentality of over a thousand men. . . . The German atrocities . . . help to bring out the brute-like bestiality which is so necessary for victory. . . . The British soldier is a kindly fellow . . . . It is necessary to corrode his mentality.Footnote 28

What Crozier describes here is a process of “combatant socialization.” In order to effectively function on the battlefield, soldiers must first be properly conditioned to their new role as a fighter.Footnote 29 Their default mentality, developed within and suitable for ordinary conditions, must be refashioned. A key aspect of this process is the nullification of interpersonal ties with the enemy. Occasionally, however, an empathetic connection with the adversary either endures or is momentarily restored on the battlefield. At particular junctures, this feeling of empathy may be sufficiently intense as to function as a circuit breaker on intercombatant violence.

Recall again the earlier example of Emilio Lussu. The act of smoking a cigarette “formed an invisible link” between him and the Austrian officer, sufficient to overcome the insider-outsider dualism that typically characterizes the battlefield. In another example of battlefield mercy from the First World War, Ernst Jünger describes an encounter in which he was poised to kill a French soldier. At the last moment, however, the panicked Frenchman displayed a photo of himself, surrounded by family. “It was a plea from another world,” writes Jünger.Footnote 30 This reminder of normality generated empathy and sympathy within Jünger powerful enough to briefly upset the violent dynamic that would otherwise govern his relationship with the enemy.

We must be careful not to overstate the role of empathy. Paul Bloom has argued convincingly that in certain conditions empathy can function as a precursor to cruelty, rather than compassion.Footnote 31 Interrogators, for example, routinely employ empathetic tools against subjects to extract information and expose psychological weaknesses that can then be exploited.Footnote 32 In war, conditions that would motivate mercy in one combatant may affect no behavioral change at all within another. In addition to empathy, an important attribute of the merciful soldier is a capacity and willingness to self-reflect on his or her own moral conduct.


Mercy is not a universal impulse—war could not function if it were. Most combatants dispense their violence dutifully, taking no great pleasure in the act of killing but committing to it nevertheless. And there are others still who do derive a joy from the taking of life. According to one former soldier, “It's frightening and unpleasant to kill, you think, but you soon realize that what you really find objectionable is shooting someone point-blank. Killing en masse, in a group, is exciting, even—and I've seen this myself—fun.”Footnote 33

Some combatants have likened killing to a sexually pleasurable act,Footnote 34 while others have described battle as a “narcotic.”Footnote 35 What then are we to make of the opposite compulsion? Beyond empathy and target vulnerability, what was it that inspired Emilio Lussu, Ernst Jünger, and others to extend mercy to those not entitled to it, at least according to the explicit rules of war? While it is beyond the scope of this article to offer anything more than preliminary speculation on this matter, some insight can be drawn from Hannah Arendt's work on fascism. Arendt argued that rule compliance, an ordinarily positive attribute, may cease to be a virtue when the rules themselves lead to morally problematic outcomes:

All our experiences tell us that it was precisely the members of respectable society, who had not been touched by the intellectual and moral upheaval in the early stages of the Nazi period, who were the first to yield. They simply exchanged one system of values against another.Footnote 36

Arendt went on to argue that the most essential characteristic of the domestic opponents of Nazism was not a “highly developed intelligence or sophistication in moral matters, but rather the disposition to live together explicitly with oneself.”Footnote 37 Conscience, navigated through self-reflection, helps to direct our moral choices: it sets the terms of who we wish to be, and evaluates our conduct in light of these terms.Footnote 38 Interaction with the self is a common feature among the men and women who feel compelled to exercise supererogatory restraint in battle. Rather than simply being good or magnanimous, they are self-reflective. They know themselves enough to recognize that if they kill in a specific moment, then an essential and irretrievable part of themselves will be lost. J. Glenn Gray spoke to this when he wrote:

There is a line that a man dare not cross, deeds he dare not commit, regardless of orders. . . . For such deeds would destroy something in him he values more than life itself. He may decide that his commander, his army, or his people may justly demand his life but may not command him to do what is in violation of his deepest self.Footnote 39

Having outlined the nature of, and common motivators for, supererogatory restraint, the following section will explore the significance of this concept in relation to our ongoing efforts to understand and refine contemporary war.

The Significance of Battlefield Supererogation

Sensitive to the political cost of military interventions, particularly those that fail to deeply engage the national interest, Western powers have increased their investment in less intrusive, lower-risk modes of warfare. One aspect of this shift has been a growing reliance on clandestine Special Operations Forces. Alongside this, Western militaries have undertaken “danger-proofing”—that is, providing enhanced protective measures for ground-based troops, combined with investment in stand-off weapons and distancing technology, including armed unmanned aerial vehicles (UAVs).Footnote 40

The remainder of this article will explore these changes in the character of war through the lens of supererogation. As Christian Enemark notes, military ethics can be divided between two approaches: the dominant “sword approach” and the “shield approach.”Footnote 41 The former is primarily concerned with establishing practical and morally defensible standards by which combatants can use violence justly. The latter, in contrast, focuses on the moral wellbeing of warriors themselves. Recognition of the supererogatory dimensions of armed conflict can and should inform our approach to both the sword and shield accounts of military ethics.

Sword Approach: Supererogation and the Rules of War

Special Operations Forces (SOFs) are an increasingly dominant feature of contemporary Western warfare. In 2013 a leaked U.K. Ministry of Defence study claimed that greater numbers of SOFs were needed in light of an increasingly “casualty averse” public.Footnote 42 In 2014, U.S. Special Operations Forces were operating in 134 countries.Footnote 43 That same year, retiring head of the U.S. Joint Special Operations Command, Admiral William McRaven, referred to the current period as “the golden age of special operations.”Footnote 44

SOFs have been utilized by the West for a range of tasks, including surveillance, reconnaissance, and airpower support. American, Australian, and British SOFs have also been heavily involved in search and destroy missions. From 2009 onward, SOFs in Afghanistan operated an effective kill list, methodically eliminating senior Taliban commanders as well as mid-level Taliban leaders.Footnote 45 These “intense operations” were “designed to kill as many Taliban commanders as possible.”Footnote 46 While many have praised the military effectiveness of these search and destroy missions, others have voiced criticism—including concern that the disproportionate focus on targeted killing has degraded the ethical status of SOFs.Footnote 47

Chris Masters highlights a number of cases of alleged misconduct in Afghanistan by the Australian special forces, including accusations of violence against “shopkeepers and tailors,” individuals with no affiliation with the Taliban.Footnote 48 In 2018 members of the Australian special forces were accused of executing a bound Afghan man by kicking him over a cliff edge. These same soldiers, it is alleged, had posted a kill list on the door of their barracks in order to record their death tally.Footnote 49 The soldiers were highly trained and presumably cognizant of their criminal liability for the unlawful killing. What they lacked (if we are to believe the charges) was a code of honor, one that encouraged both empathy with the “other” and moral reflection with the “self.”

Comprehensive training, strict orders, and effective sanctions are necessary but insufficient motivators of appropriate conduct in battle. According to a 2005 study by the International Committee of the Red Cross (ICRC), mere knowledge of, or even a favorable attitude toward, existing rules does not necessarily translate into higher levels of compliance.Footnote 50 In a subsequent study focusing exclusively on battlefield restraint, the ICRC argued that the most effective way to narrow the gap between rule awareness and rule compliance in war is to encourage individuals, through socialization, to internalize the foundational values represented by the law.Footnote 51 “Value-based motivation,” the study claimed, including a commitment to “warrior's honor,” is as powerful a determinant of combatant behavior as the threat of punishment.Footnote 52

This highlights the need for greater engagement with the supererogatory dimensions of war. Supererogatory restraint is constituted by values that when cultivated also incentivize adherence to the more explicit rules and standards of the battlefield. This is not to argue that battlefield mercy must be encouraged as the default behavior of combatants in war. Enemy soldiers, even those acutely vulnerable at the moment of targeting, retain their liability to harm.Footnote 53 As noted, combatants are not obligated to spare the life of opponents who have not surrendered or been rendered hors de combat, but this does not mean that we should disregard their impulse to do otherwise.

War is more rule bound today than at any other time in history. It remains a setting, however, in which the gravest matters of life and death are routinely adjudicated by individuals answerable to no authority beyond their own conscience. It is partly for this reason, John Keegan stresses, that “there is no substitute for honor as a medium for enforcing decency on the battlefield, never has been and never will be.”Footnote 54 This is especially true in relation to SOFs, the members of which routinely operate in the absence of sustained oversight and accountability.Footnote 55

Supererogatory action provides moral agents with the chance to express virtuous traits of character and to conduct themselves in accordance with their own values—opportunities denied to them within the impersonal moral framework of duty and obligation.Footnote 56 Even if these combatants forgo the exercise of battlefield mercy, the factors that motivate it—empathy, self-reflection, and restraint in response to defenselessness—should be instilled as essential virtues. This is particularly necessary as we gain greater awareness of the causes and consequences of moral injury in war.

Shield Approach: Supererogation and Moral Injury

Harriett Jackson Brown, Jr. famously wrote, “Twenty years from now, you will be more disappointed by the things you didn't do than by the ones you did.” While I have never fought in war, I suspect that for many who have the opposite is true. War has long been described as an existential and transformative experience—a realm within which combatants are able to “find the definition of their whole being.”Footnote 57 For some, though certainly not all, this transformation is characterized more by shame than glory. According to Jennifer Manion, moral shame results from the personal failure to meet one's own moral ideals.Footnote 58 This shame can, in turn, generate moral injury; that is, damage inflicted upon combatants by a disharmony between their own ethical values and their specific conduct in battle. Diane Silver describes moral injury as “a deep soul wound that pierces a person's identity, sense of morality, and relationship to society.”Footnote 59 This condition can have a debilitating impact on the lives of combat veterans, leading to serious depression and in extreme cases even suicide.Footnote 60

The Moral Injury Project at Syracuse University lists a number of examples of moral injury–inducing acts in war. These include killing civilians either intentionally or unintentionally, giving an order that results in the injury or death of one's own personnel, failing to come to the aid of a fellow service member or civilian, discovering that local nationals one has worked alongside have been executed, failing to report sexual violence, and following orders that were illegal or immoral.Footnote 61 Each of these examples involves an objectively wrongful act. The moral injury itself is triggered by the combatant's proximity to this wrong, either as the deliberate or accidental author of the wrong itself or as a helpless bystander.

Similar descriptions can be found across the literature. Moral injury, it is commonly argued, results from an act of “transgression”;Footnote 62 from “violations” or “betrayals” of accepted behavior;Footnote 63 or from “inhumane,” “depraved,” or “cruel” acts.Footnote 64 According to Wayne Chappelle, the catalyst for moral injury is “intentionally doing something that you felt was against what you thought was right.”Footnote 65 These definitions are all problematic, however, because they provide an overly narrow criterion for moral injury. Though the causes of this condition include unambiguously wrongful acts, crucially, we must also consider situations in which combatants are forced to choose between incommensurable moral goods; specifically, between mercy and the duty to kill.

Most cases of intercombatant restraint sit in tension with the military duty to take enemy life. Our understanding of moral injury needs to expand to better encompass this tension. Consider the following example from Afghanistan, in which a twenty-two-year-old American soldier killed an Afghan boy:

Here's Nick, pausing in a lull. He spots somebody darting around the corner of an adobe wall, firing assault rifle shots at him and his Marines. Nick raises his M-4 carbine. He sees the shooter is a child, maybe 13. With only a split second to decide, he squeezes the trigger and ends the boy's life. . . . There is a long silence after Nick finishes the story. He's lived with it for more than three years and the telling still catches in his throat. Eventually, he sighs. “He was just a kid. But I'm sorry, I'm trying not to get shot and I don't want any of my brothers getting hurt, so when you are put in that kind of situation . . . it's shitty that you have to, like . . . shoot him. You know it's wrong. But . . . you have no choice.”Footnote 66

It is important to be precise regarding the nature of this self-reported wrong. According to the ethics and laws of war, the child, though morally innocent on account of insufficient cognitive capacity, was directly participating in hostilities and thus liable to be killed. Mercy in this context would not have been in accordance with the explicit rules of war, but rather Nick's own ethical code. It would have been an act of supererogation.

In our efforts to understand and treat moral injury in war, it is essential to look beyond explicit violation and confront the true moral complexities of battle. Specifically, we must acknowledge the severe mental harm that may sometimes be inflicted upon the combatant as a consequence of following the rules of war. Recognition of this fact is crucial if we are to properly comprehend the implications of remotely operated warfare and, specifically, the vulnerability of UAV operators to moral injury.

UAVs and Moral Injury

Debate is ongoing regarding the extent to which armed UAVs comply with or diverge from the moral and legal standards of war. Supporters of this technology highlight the potential of UAVs to surpass battlefield alternatives in relation to both discrimination and proportionality.Footnote 67 Kenneth Anderson describes UAVs as a “humanitarian technology” and a “major step forward toward a much more discriminating use of violence in war and self-defence.”Footnote 68 Others dispute this claim, arguing that the capability of UAVs to mitigate collateral civilian damage has been overstated. According to one report, UAV strikes in non-battlefield settings resulted in thirty-five times more civilian fatalities than manned airstrikes.Footnote 69

Further disagreement surrounds the distancing aspect of UAVs, and the extent to which this enhances or undermines their ethical status. Some have argued the latter, that UAVs encourage a “‘Playstation’ mentality to killing”—a psychological disconnectedness among operators that relaxes inhibitions on violence.Footnote 70 The actual evidence, however, suggests something closer to the opposite. It is true that UAVs physically dislocate the operator from the act (and reciprocal threat) of death to a historically unprecedented degree. At the same time, however, the video feedback technology of this weaponry maintains, and even enhances, the intimacy of such violence. John Williams refers to this phenomenon as “distant intimacy.”Footnote 71

As argued above, combatants are more likely to exercise supererogatory restraint in battle, or at least feel inclined to, when the cognitive partition between normal society and the domain of war erodes. UAV operators are particularly susceptible to such an erosion given the nature of their work.Footnote 72 Those operators located in the United States and United Kingdom are required to mentally transition between war and peace at the start and conclusion of every shift, sometimes multiple times a day.Footnote 73 Retired UAV operator Jeff Bright stressed the disorientating nature of this transition: “I'd literally just walked out on dropping bombs on the enemy, and 20 minutes later I'd get a text—can you pick up some milk on your way home?”Footnote 74

Complicating this further is the frequency with which UAV operators are required to kill individuals who pose no physical threat at the precise moment of contact. When battle strays too far outside the limits of self-defense, those empowered by such an advantage may grow to doubt their own license to kill. Staff sergeant Brandon Bryant, who operated Predator UAVs between 2005 and 2011, described one incident with particular regret: “We waited for those men to settle down in their beds and then we killed them in their sleep. That was cowardly murder.”Footnote 75 In another example, a British Reaper operator destroyed a truck while attempting to kill two suspected ISIS members. Soon after, the two suspects reemerged to investigate the destroyed vehicle, prompting a surge of empathy from the UAV operator: “I felt sorry for them. I felt some association with them because my dad used to take me for drives in trucks where he used to work.”Footnote 76 This empathetic connection intensified when, in response to the sound of the incoming Hellfire missile, one of the targets threw himself onto the other:

And that just stuck in my head. I don't know why it's affected me. I don't know if it was the affinity with my father and the truck. I believe they were father and son because of the way the one threw himself on top of the other. And they were both lying there, dead. It's just something that's always stuck with me. They were just men like me.Footnote 77

The intimate nature of UAV violence leaves open the possibility of empathetic ties with the enemy. This may, in turn, translate into a discomfort with the taking of life. “At some point,” notes Air Force Colonel Hernando Ortega, “you might gain a level of familiarity that makes it a little difficult to pull the trigger.”Footnote 78 This is not to argue that UAV operators will exercise supererogatory restraint at higher levels than other participants in war.Footnote 79 In none of the examples listed above was the target spared. What these accounts should provoke, however, is a greater appreciation of the vulnerability of UAV operators to moral injury. In a recent survey, drawn from interviews with 141 intelligence analysts and officers involved in remote combat operations, three-quarters of respondents reported “negative, disruptive emotions,” including “grief, remorse, and sadness.”Footnote 80 Further analysis is needed to assess the extent to which these feelings emanate from an unrealized urge to exercise battlefield mercy.

There exists a range of quality scholarship exploring the relationship between remotely operated warfare and supererogation. At present, however, this analysis has primarily focused on the alleged incompatibility between UAVs and the battlefield virtue of physical courage.Footnote 81 Greater attention must be given to the subject of restraint and, specifically, to the connection between a failure to extend battlefield mercy and moral injury.Footnote 82

UAV operators retain the right to refuse a request to kill a target. Once authorization has been given, however, there is unsurprisingly significant, albeit indirect, pressure to fire.Footnote 83 Downward pressure comes from commanders at operational headquarters, while upward pressure comes from fellow soldiers fighting on the ground who may justifiably object when they perceive that their own risk has increased as a consequence of a UAV operator refusing a seemingly valid request to fire. To what extent does this intense and multidirectional scrutiny affect the supererogatory instinct of the operator?

We should also consider the extent to which this instinct fluctuates depending on the precise nature of the battlefield encounter. UAV operators consistently report high levels of pride and moral satisfaction when performing troop overwatch, which involves close air support of friendly forces fighting on the ground.Footnote 84 How does this compare to the premeditated killing of specific individuals? Moreover, does the desire to exercise supererogatory restraint differ depending on whether the target has been designated high or low value? Does the background of the operator matter? Are former aircraft pilots turned UAV operators more or less sensitive to the appeal of battlefield mercy than those recruited directly from civilian life? Is the gender of the operator significant? The answers to these and other questions can enrich our understanding of the precise relationship between remotely operated warfare, supererogation, and moral injury.


“The killing of an individual enemy,” argued two military officers, “with a rifle, grenade, bayonet—yes, even the bare hands—is the mission of the Army . . . this mission has no civilian counterpart.”Footnote 85 This statement reflects a position long held by many regarding the fundamental discontinuity between war and peace. In order to fight war effectively, its participants must at least partly divorce themselves from the values and expectations that constitute appropriate conduct in normal society. It would be a mistake, however, to view such a divorce as either straightforward or immutable. Even when justified, there is a cost to the taking of life, one that some combatants some of the time may be disinclined to pay.

This article has examined the role of supererogatory restraint in war—situations in which combatants go beyond their moral and legal duties to extend additional protections to the enemy. A more complete understanding of the factors that motivate battlefield mercy will enhance our efforts to create more effective systems of rule compliance. This is of particular relevance to the Special Operations Forces, the members of which frequently engage in targeted killing operations in the absence of sufficient oversight.

The study of supererogation is of equal utility when grappling with the origins and the implications of moral injury. Research into the causes of this condition must be broadened to encompass more than explicit battlefield transgressions. Crucially, it must also include acts of violence that while morally and legally permissible nevertheless invoke within the combatant a sense of deep disquiet. An appreciation of this tension is especially important as we increase our investment in remotely operated modes of warfare. UAVs enable the complete physical dislocation of combatants from the battlefield. The enduring intimacy of this violence, however, ensures that operators are neither psychologically nor psychically divorced from the kill. Going forward, a greater appreciation of the impulse to exercise supererogatory restraint in battle is essential when calculating the unintended costs of putatively risk-free violence.



I would like to thank Andrew Dougall, Andrew Flescher, Josie Hornung, Sebastian Kaempf, Jacinta O'Hagan, Sarah Percy, Megan Price, Melinda Rankin, Christian Reus-Smit, Ryan Smith, Stan Steindl, Mark Timmons, and the four anonymous reviewers of this article for their insightful comments.


1 Sherman, William T., “Letter of William T. Sherman to James M. Calhoun, E. E. Rawson, and S. C. Wells, September 12, 1864,” in Sherman's Civil War: Selected Correspondence of William T. Sherman, 1860–1865, Berlin, Jean V. and Simpson, Brooks D., eds. (Chapel Hill: University of North Carolina Press, 1999), pp. 707–9Google Scholar,

2 See, for example, Bassiouni, M. Cherif, “The New Wars and the Crisis of Compliance with the Law of Armed Conflict by Non-State Actors,” Journal of Criminal Law and Criminology 98, no. 3 (March 2008), pp. 711810Google Scholar; Búzás, Zoltán I., “Evading International Law: How Agents Comply with the Letter of the Law but Violate Its Purpose,” European Journal of International Relations 23, no. 4 (November 2016), pp. 857–83CrossRefGoogle Scholar; Cassese, Antonio, “Current Challenges to International Humanitarian Law,” in Clapham, Andrew and Gaeta, Paola, eds., The Oxford Handbook of International Law in Armed Conflict (Oxford: Oxford University Press, 2014)Google Scholar; and Cogan, Jacob Katz, “Noncompliance and the International Rule of Law,” Yale Journal of International Law 31 (2004), pp. 189210Google Scholar.

3 Horgan, Terry and Timmons, Mark, “Untying the Knot from the Inside Out: Reflections on the ‘Paradox’ of Supererogation,” Social Philosophy and Policy 27, no. 2 (2010), p. 32CrossRefGoogle Scholar.

4 Urmson, J. O., “Saints and Heroes,” in Melden, Abraham Irving, ed., Essays in Moral Philosophy (Seattle: University of Washington Press, 1958), p. 208Google Scholar.

5 Lussu, Emilio, quoted in Walzer, Michael, Just and Unjust Wars: A Moral Argument with Historical Illustrations (New York: Basic Books, 2006), p. 141Google Scholar.

6 Ibid., p. 143.


7 Dinstein, Yoram, “The System of Status Groups in International Humanitarian Law,” in von Heinegg, Wolff Heintschel and Epping, Volker, eds., International Humanitarian Law Facing New Challenges: Symposium in the Honour of Knut Ipsen (Berlin: Springer, 2007), p. 144Google Scholar.

8 Army Doctrine Publication, cited in Taylor, Claire, Armed Forces Covenant (London: House of Commons, June 9, 2011), p. 2Google Scholar (emphasis added),

9 Uniform Code of Military Justice, 10 U.S.C. §§ 801–940 (1964),

10 Emilio Lussu, quoted in Walzer, Just and Unjust Wars, p. 142.

11 Hare, Richard Mervyn, Moral Thinking: Its Levels, Method, and Point (Oxford: Oxford University Press, 1981)CrossRefGoogle Scholar; and Heyd, David, Supererogation: Its Status in Ethical Theory (Cambridge, U.K.: Cambridge University Press, 1982)Google Scholar.

12 Kamm, Frances Myrna, “Supererogation and Obligation,” Journal of Philosophy 82, no. 3 (March 1985), p. 118CrossRefGoogle Scholar.

13 Ibid., pp. 119–20.


14 Eisenberg, Theodore and Garvey, Stephen P., “The Merciful Capital Juror,” Ohio State Journal of Criminal Law 2, no. 1 (Fall 2004), p. 165Google Scholar; and Rainbolt, George, “Mercy: In Defence of Caprice,” Noûs 31, no. 2 (June 1997), pp. 235–36CrossRefGoogle Scholar.

15 Benbaji, Yitzhak, “A Defense of the Traditional War Convention,” Ethics 118, no. 3 (April 2008), p. 466CrossRefGoogle Scholar; and Gross, Michael L., “Assassination and Targeted Killing: Law Enforcement, Execution or Self-Defence?,” Journal of Applied Philosophy 23, no. 3 (August 2006), p. 329CrossRefGoogle Scholar.

16 Morkevičius, Valerie, “Tin Men: Ethics, Cybernetics and the Importance of Soul,” Journal of Military Ethics 13, no. 1 (May 2014), pp. 57CrossRefGoogle Scholar.

17 Newton, Michael A. and May, Larry, Proportionality in International Law (New York: Oxford University Press, 2014), pp. 7374Google Scholar.

18 Dinstein, Yoram, “Legal and Ethical Lessons of NATO's Kosovo Campaign,” in Wall, Andru E., ed., International Law Studies 78 (2002), p. 153Google Scholar.

19 Glover, Michael, Humanity: A Moral History of the Twentieth Century (London: Pimlico, 2001), p. 53Google Scholar.

20 Quoted in ibid., p. 53.

21 Eisenberg and Garvey, “Merciful Capital Juror,” p. 169.

22 Lieber, Francis, Manual of Political Ethics, Part 2: Political Ethics Proper (for the use of colleges and students in law) (Boston, USA: Charles C Little and James Brown, 1876), p. 660Google Scholar.

23 This ambiguity can also be found at the level of jus ad bellum in the disagreement over what exactly constitutes an “imminent threat.” The United States is among those that have sought to reinterpret and expand the concept of imminence to include less immediate and pressing threats. Critics fear that such efforts stretch the concept “beyond recognition.” See Michael W. Lewis, “Elongated Imminence and Operational Realities,” Opinio Juris, January 29, 2013,; and U.S. Department of Justice, “Lawfulness of a Lethal Operation Directed against a U.S. Citizen Who Is a Senior Operational Leader of Al-Qa'ida or an Associated Force” (white paper, U.S. Department of Justice, November 8, 2011),

24 Lamm, Claus, Batson, C. Daniel, and Decety, Jean, “The Neural Substrate of Human Empathy: Effects of Perspective-Taking and Cognitive Appraisal,” Journal of Cognitive Neuroscience 19, no. 1 (February 2007), p. 42CrossRefGoogle ScholarPubMed.

25 Thompson, Evan, Mind in Life: Biology, Phenomenology and the Sciences of the Mind (Cambridge, Mass.: Belknap Press of Harvard University Press, 2007), p. 388Google Scholar.

26 Gray, Jesse Glenn, The Warriors: Reflections on Men in Battle (Lincoln: University of Nebraska Press, 1998), p. 159Google Scholar.

27 Grossman, Dave, On Killing: The Psychological Cost of Learning to Kill in War and Society (New York: Back Bay Books, 2009)Google Scholar.

28 Crozier, F. P., A Brass Hat in No Man's Land (London: C. Chivers, 1950), p. 42Google Scholar.

29 Dara Kay Cohen explores the process of combatant socialization in relation to the war crime of gang rape. Multiple perpetrator rape, Cohen argues, may function as a tool for armed group cohesion, communicating norms of virility, masculinity, brutality, and loyalty. See Cohen, Dara Kay, “The Ties that Bind: How Armed Groups Use Violence to Socialize Fighters,” Journal of Peace Research 54, no. 5 (September 2017), p. 701CrossRefGoogle Scholar.

30 Jünger, Ernst, Storm of Steel, trans. Hofmann, Michael (New York: Penguin Books, 2004), p. 234Google Scholar.

31 Bloom, Paul, Against Empathy: The Case for Rational Compassion (London: Bodley Head, 2016)Google Scholar.

32 Bloche, M. Gregg and Marks, Jonathan H., “When Doctors Go to War,” New England Journal of Medicine 352, no. 1 (January 2005), pp. 36CrossRefGoogle ScholarPubMed.

33 Quoted in Glover, Humanity, pp. 54–55.

34 Bourke, Joanna, An Intimate History of Killing: Face-to-Face Killing in Twentieth-Century Warfare (London: Granta Books, 1999)Google Scholar.

35 Babchenko, Arkady, One Soldier's War in Chechnya (New York: Routledge, 2007), p. xGoogle Scholar.

36 Arendt, Hannah, “Personal Responsibility under Dictatorship,” Listener 72, no. 1845 (1964), p. 44Google Scholar (emphasis in original).

37 Ibid., p. 44.


38 Morkevičius, “Tin Men,” p. 4.

39 Gray, The Warriors, p. 186.

40 Waldman, Thomas, “Vicarious Warfare: The Counterproductive Consequences of Modern American Military Practice,” Contemporary Security Policy 39, no. 2 (April 2018), pp. 192–95CrossRefGoogle Scholar. Waldman also highlights a third approach—delegation—which involves shifting the burden of risk to proxy forces, including private military and security companies, irregular militias, and other indigenous forces.

41 Enemark, Christian, “Drones, Risk, and Moral Injury,” Critical Military Studies 5, no. 2 (October 2017), p. 155Google Scholar.

42 Ministry of Defence, quoted in Ben Quinn, “MoD Study Sets Out How to Sell Wars to the Public,” Guardian, September 26, 2013,

43 Nick Turse, “US Special Operations Forces Are in More Countries than You Can Imagine,” Nation, January 20, 2015,

44 William McRaven, quoted in Dan Lamothe, “Retiring Top Navy SEAL: ‘We Are in the Golden Age of Special Operations,’” Washington Post, August 29, 2014,

45 Moran, Jon, “Time to Move Out of the Shadows? Special Operations Forces and Accountability in Counter-Terrorism and Counter-Insurgency Operations,” University of New South Wales Law Journal 39, no. 3 (2016), pp. 1241–42Google Scholar.

46 Richard Norton-Taylor, “Talking about Taliban Killers Is Taboo in the UK,” Guardian, December 7, 2011,

47 “Australian Special Forces Veteran Breaks Silence on ‘Insidious, Infectious’ Culture,” ABC (Australian Broadcasting Corporation), July 9, 2017,

48 Masters, Chris, No Front Line: Australian Special Forces at War in Afghanistan (Sydney: Allen & Unwin, 2017), p. 490Google Scholar.

49 Chris Masters and Nick McKenzie, “Standing Up, Not Shooting: The ‘Compassionate Psychopaths’ of the SAS,” Sydney Morning Herald, August 4, 2018,

50 Daniel Muñoz-Rojas, Jean-Jacques Frésard, and International Committee of the Red Cross, The Roots of Behaviour in War: Understanding and Preventing IHL Violations (Geneva: International Committee of the Red Cross, 2005), pp. 196–97.

51 International Committee of the Red Cross, The Roots of Restraint in War (Geneva: International Committee of the Red Cross, 2018), p. 9.

52 Ibid., pp. 32–33.


53 Renic, Neil C., “Justified Killing in an Age of Radically Asymmetric Warfare,” European Journal of International Relations 25, no. 2 (June 2019), pp. 408–30CrossRefGoogle Scholar.

54 Keegan, John, “If You Won't, We Won't: Honour and the Decencies of Battle,” Times Literary Supplement, no. 4834 (November 24, 1995), p. 11Google Scholar.

55 Moran, “Time to Move Out of the Shadows?,” p. 1240.

56 Heyd, Supererogation, p. 10.

57 Morison, Elting E., Men, Machines, and Modern Times (Cambridge, Mass.: MIT Press, 1966), p. 34Google Scholar.

58 Manion, Jennifer C., “The Moral Relevance of Shame,” American Philosophical Quarterly 39, no. 1 (January 2002), p. 77Google Scholar.

59 Diane Silver, “Beyond PTSD: Soldiers Have Injured Souls,” Pacific Standard, January 22, 2015,

60 Shira Maguen and Brett Litz, “Moral Injury in the Context of War,” National Center for PTSD, n.d.,

61 “What Is Moral Injury,” Moral Injury Project, Syracuse University, n.d.,

62 Jesse Kirkpatrick, “Military Drone Operators Risk a Serious Injury: And It's One You Might Not Expect,” Slate, January 26, 2016,; Maguen, Shira and Litz, Brett, “Moral Injury in Veterans of War,” PTSD Research Quarterly 23, no. 1 (January 2012), p. 1Google Scholar; and Maguen and Litz, “Moral Injury in the Context of War.”

63 Frankfurt, Sheila B., Frazier, Patricia, and Engdahl, Brian, “Indirect Relations between Transgressive Acts and General Combat Exposure and Moral Injury,” Military Medicine 182, nos. 11/12 (November/December 2017), p. 1950CrossRefGoogle ScholarPubMed.

64 Drescher, Kent D., Foy, David W., Kelly, Caroline, Leshner, Anna, Schutz, Kerrie, and Litz, Brett, “An Exploration of the Viability and Usefulness of the Construct of Moral Injury in War Veterans,” Traumatology 17, no.1 (March 2011), pp. 2, 813CrossRefGoogle Scholar.

65 Wayne Chappelle, quoted in Eyal Press, “The Wounds of the Drone Warrior,” New York Times, June 13, 2018, The definition of moral injury remains contested and has yet to be fully accepted by the military and psychological community.

66 David Wood, “The Grunts: Damned If They Kill, Damned If They Don't,” Huffington Post, March 18, 2014,

67 “Drones are Ethical and Effective,” YouTube video, 8:42, from a speech given by Kenneth Anderson, posted by Oxford Union, May 3, 2013,; “The Efficacy and Ethics of U.S. Counterterrorism Strategy,” webcast, 1:09, from a speech given by John Brennan at the Woodrow Wilson Center, May 1, 2012,; Brunstetter, Daniel and Braun, Megan, “The Implications of Drones on the Just War Tradition,” Ethics and International Affairs 25, no. 3 (Fall 2011), pp. 337–58CrossRefGoogle Scholar, 348; Fricker, Matthew, Plaw, Avery, and Williams, Brian Glyn, “New Light on the Accuracy of the CIA's Predator Drone Campaign in Pakistan,” Terrorism Monitor 8, no. 41 (November 2010), p. 8Google Scholar; and Strawser, Bradley Jay, “Moral Predators: The Duty to Employ Uninhabited Aerial Vehicles,” Journal of Military Ethics 9, no. 4 (2010), pp. 342–68CrossRefGoogle Scholar.

68 Rise of the Drones: Unmanned Systems and the Future of War, 111th Cong., 2nd sess. 201 (March 23, 2010) (written testimony of Kenneth Anderson, Professor of Law, American University Washington College of Law), p. 12,

69 Micah Zenko and Amelia Mae Wolf, “Drones Kill More Civilians than Pilots Do,” Foreign Policy, April 25, 2016,

70 United Nations General Assembly, “Report of the Special Rapporteur on Extrajudicial, Summary or Arbitrary Executions, Philip Alston,” A/HRC/14/24/Add.6, May 28, 2010, p. 25,; Claire Finkelstein, “Targeted Killing as Pre-Emptive Action,” in Claire Finkelstein, Jens David Ohlin, and Andrew Altman, eds., Targeted Killings: Law and Morality in an Asymmetrical World (Oxford: Oxford University Press, 2011), p. 174; Chris Cole, Convenient Killing: Armed Drones and the “PlayStation” Mentality (Oxford: Fellowship of Reconciliation, 2010); and Peter Olsthoorn, Military Ethics and Virtues: An Interdisciplinary Approach for the 21st Century (New York: Routledge, 2011), p. 126.

71 Williams, John, “Distant Intimacy: Space, Drones, and Just War,” Ethics and International Affairs 29, no. 1 (March 2015), p. 93CrossRefGoogle Scholar.

72 Enemark, “Drones, Risk, and Moral Injury,” p. 11.

73 Lee, Peter, Reaper Force: Inside Britain's Drone Wars (London: John Blake, 2018), pp. 3839Google Scholar.

74 Jeff Bright, quoted in Press, “Wounds of the Drone Warrior.”

75 Brandon Bryant, quoted in Ed Pilkington, “Life as a Drone Operator: ‘Ever Step on Ants and Never Give It Another Thought?,” Guardian, November 19, 2015,

76 Toby, quoted in Lee, Reaper Force, p. 224.

77 Toby, quoted in ibid., p. 224.

78 Hernando Ortega, quoted in Elisabeth Bumiller, “A Day Job Waiting for a Kill Shot a World Away,” New York Times, July 29, 2012,

79 Lee, Reaper Force, pp. 278–79. British Reaper operators most often express concern in one of two ways: first, that they might accidently kill noncombatants; and second, that they might miss (or be prevented from taking) a shot against an individual who would then go on to commit further violence.

80 Quoted in Press, “Wounds of the Drone Warrior.”

81 Enemark, Christian, Armed Drones and the Ethics of War: Military Virtue in a Post-Heroic Age (London: Routledge, 2013)CrossRefGoogle Scholar; French, Shannon E., Sisk, Victoria, and Bass, Caroline, “Drones, Honor, and Fragmented Sovereignty: The Impact of New and Emerging Technology on the Warrior's Code,” in Brunstetter, Daniel R. and Holeindre, Jean-Vincent, eds., The Ethics of War and Peace Revisited: Moral Challenges in an Era of Contested and Fragmented Sovereignty (Washington, D.C.: Georgetown University Press, 2018)Google Scholar; Kirkpatrick, Jesse, “Drones and the Martial Virtue Courage,” Journal of Military Ethics 14, no. 3–4 (October 2015), pp. 202–19CrossRefGoogle Scholar; Renic, Neil C., “UAVs and the End of Heroism? Historicising the Ethical Challenge of Asymmetric Violence,” Journal of Military Ethics 17, no. 4 (March 2019), pp. 188–97CrossRefGoogle Scholar; Sparrow, Robert, “War without Virtue?,” in Strawser, Bradley Jay, ed., Killing by Remote Control: The Ethics of an Unmanned Military (Oxford: Oxford University Press, 2013), pp. 9899Google Scholar; and Tonkens, Ryan, “The Case against Robotic Warfare: A Response to Arkin,” Journal of Military Ethics 11, no. 2 (August 2012), pp. 149–68CrossRefGoogle Scholar.

82 One article that does address this issue is Enemark, “Drones, Risk, and Moral Injury.”

83 French, Sisk, and Bass, “Drones, Honor, and Fragmented Sovereignty,” pp. 213–15.

84 Lee, Reaper Force, p. 95; and Matthew Power, “Confessions of a Drone Warrior,” GQ, October 23, 2013,

85 Quoted in Bourke, An Intimate History of Killing, p. 3.

You have Access

Send article to Kindle

To send this article to your Kindle, first ensure is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

Note you can select to send to either the or variations. ‘’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Battlefield Mercy: Unpacking the Nature and Significance of Supererogation in War
Available formats

Send article to Dropbox

To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

Battlefield Mercy: Unpacking the Nature and Significance of Supererogation in War
Available formats

Send article to Google Drive

To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

Battlefield Mercy: Unpacking the Nature and Significance of Supererogation in War
Available formats

Reply to: Submit a response

Please enter your response.

Your details

Please enter a valid email address.

Conflicting interests

Do you have any conflicting interests? *