Military Chaplains Just War Education Project

Just War and Moral Injury

The premise of the Episcopal Church’s Military Chaplains Just War Education Project is that the teachings of the Just War tradition can support military chaplains’ ministry and care to those who serve or have served in the armed forces.  In particular, the tradition’s core concepts may be relevant in addressing “moral injury” suffered by combat veterans.  The following is a perspective on moral injury and the Just War tradition offered by It was prepared by Marc Livecche, Ph.D., the McDonald Distinguished Scholar of Ethics, War, and Public Life at “Providence: A Journal of Christianity & American Foreign Policy” and an expert in this field, with editorial assistance from Matt Gobush, member of the Church’s Standing Commission on World Mission.

While Post-Traumatic Stress Disorder (PTSD) has long been recognized as a psychiatric wound among warfighters, there is an increasing recognition that something else is at play as well. Many combat veterans suffer symptoms atypical to their PTSD diagnosis. Many do not present—or do not only present—the paranoia, hyper-vigilance, or other typical responses to life-threat ordeals. Instead—or additionally—they display what is best described as soul wounds: crippling degrees of guilt, shame, sorrow, or remorse. 

These soul wounds have come to be termed “moral injury,” and designate a psychic trauma resulting from doing, allowing to be done, or having done to you that which goes against deeply held normative beliefs (Litz, 2009). This definition illuminates Vietnam combat veteran Karl Marlantes’ observation that “The violence of combat assaults psyches, confuses ethics, and tests souls. This is not only a result of the violence suffered. It is also a result of the violence inflicted” (Marlantes, 2011). 

Although the Just War tradition may provide resources for treating moral injury, it is insufficient to assert that killing a lawful enemy combatant in a just war using proportionate and discriminate force is, simply, morally permissible. This observation is motivated in part by the large numbers of psychiatric battle casualties suffered during operations in Iraq and Afghanistan; indeed, which have attended military activity throughout history. Too often, veterans stagger home from battle—even morally justified battle—suffering not necessarily from physical injuries as classically perceived but injured all the same.

Let us consider this through a particular case. In September 2010, U.S. Marine Lieutenant Timothy Kudo abetted in the slaying of two unarmed Afghan teenagers. It was an accident. His patrol had been ambushed by Taliban machine gun fire. Quickly counterattacking, the Marines were attempting to track the enemy through a village when a pair of men on a motorcycle suddenly appeared on a hill above. With their greater elevation giving them a deadly tactical advantage over the Marines, the riders slowly approached and either did not understand or simply ignored the patrol’s repeated commands and escalating warnings to stop them their advance. A set of misconceptions gave the appearance of an attack. Sticks the riders held were confused for rifles and the motorcycle’s chrome, reflecting the sun in bright flashes, gave the appearance of muzzle bursts. The Marines opened fire, killing the riders. Afterward, the Marines discovered the dead were unarmed. One of them was barely a teenager (Kudo, 2013).

Kudo left Afghanistan in 2011. Time progresses, but memories remain, and those slain Afghan teenagers are never far from his mind. Their deaths remain a source of lasting anxiety. “I think about them every day,” Kudo confesses. “I didn’t return from Afghanistan as the same person…My personality is the same… but I’m no longer the “good” person I once thought I was” (Kudo, 2013).

Significantly, Kudo does not only lament the killing of young civilians. He mourns, too, the occasions in which he permitted snipers to fire on those burying roadside explosives, or when he called in air or artillery strikes, or when he ordered assaults against enemy positions. He continues:

When I joined the Marine Corps, I knew I would kill people. I was trained to do it in a number of ways, from pulling a trigger to…beating someone to death with a rock. As I got closer to deploying to war…my lethal abilities were refined, but my ethical understanding of killing was not. I held two seemingly contradictory beliefs: Killing is always wrong, but in war, it is necessary (Kudo, 2013).

For Kudo, growing willing to kill another human being results in a diminution of what it means to be a human being: “To properly wage war,” he concludes, “you have to recalibrate your moral compass” (Kudo, 2013).

With this case in mind, my focus here is entirely on moral injury as it afflicts the moral agent. Here is where my assertion that killing comes in different kinds matters. If doing something that goes against deeply held normative beliefs leads to moral injury, it should be unsurprising that a warfighter would be morally injured following the commitment of an atrocity – for instance, the wanton killing of an innocent civilian or the gratuitous infliction of pain on an enemy combatant. Moral injury resulting from perpetrating moral evil is appropriate. Indeed, we once called this the consciousness of sin and its absence – our inability or refusal to register guilt over the wrongs we have done –is a crisis. 

However, large numbers of warfighters are suffering from having done the most basic business of war: killing the lawful enemy even under conditions commensurate with the rules of armed conflict and the guidance of moral frameworks such as the just war tradition. Why this a problem is revealed by clinical studies that identify having killed in combat – no matter the circumstances – to be the chief predictor of moral injury. Moreover, moral injury has proved to be the chief predictor of combat veteran suicide (Maguen, 2012). While other issues such as PTSD, Traumatic Brain Injuries, and increased operational tempos can be contributing factors – not least because that they can wreak havoc on servicemembers’ relationships to the very people they most depend on for holistic support and emotional stability—it remains that moral trauma is a major catalyst behind the troubling uptick of warfighters dying by their own hands, casualties of war even after battle has long-ended. 

The response to this crisis has gained significant momentum. As this special issue helps to indicate, an increasing array of clinical studies, scholarly and popular monographs, edited books, articles, and papers, treatment facilities and regimes, training seminars, and conferences have been deployed to educate, equip, and support both warfighters and those who care for them. Nevertheless, deficiencies remain.

Sometime ago I participated in an Operational Religious Support Leaders Training (ORSLT) conference for the U.S. Army. ORSLT is convened by the Office of the Chaplains to strengthen the religious support readiness posture of Chaplain sections, Unit Ministry Teams (UMTs), and Religious Support Teams (RSTs) assigned to a given theater of operations. 

One of the plenary talks was given by a senior chaplain with significant theological and academic training, operational experience, and subject matter expertise regarding moral injury. He delivered an excellent presentation helping to identify the foundations of, and the similarities and differences between, PTSD and moral injury, to recognize the possibility for post-traumatic growth, and to illuminate the role of military religious support teams in leading combat veterans into that growth. The chaplain defined moral injury in essentially the same terms as I have here—as an injury that results when soldiers violate their core moral beliefs and thereby feel they no longer live in a reliable, meaningful world and can no longer be regarded as decent human beings. In discussing what the morally injured require, the chaplain pointed to forgiveness, healing—such as might be found in the healing rituals performed by Native Americans, African tribes, Japanese Samurai, or religious penitential systems; reconciliation; and meaning and purpose—such as might occur by finding avenues through moral trauma and into post-traumatic growth: increased maturity, new wisdom, and the like.

But if I am right that it is wrong to insist without qualification that killing in war is morally evil, even when necessary to avert a greater moral evil, then not all killing in war ought necessarily to lead to moral injury because not all killing in war is necessarily morally injurious. 

Asserting this may prove insufficient to resolve the crisis, however. For instance, we may know that what we have done is not morally blameworthy and yet still suffer moral injury for it, as might occur – as it did with Kudo – following an accidental killing. Imagine a scenario in which a conscientious driver accidentally strikes and kills a child. Even if fault rested entirely with the poor child and the accident was undeniably unavoidable, it is reasonable that the symptoms of moral injury – grief, remorse, shame – would afflict the driver, even to crippling degrees. 

Nevertheless, when one is mistaken about the truth, especially when the stakes are high, it is most times meet and just to correct them. Particularly when the false belief is dangerous, as it is dangerous, even lethally so, to believe that all killing is morally injurious, charity demands a correction. I want to help warfighters and those who care for them to reevaluate false beliefs about what it means to kill in war, to interrogate deeply held principles and, where necessary, to adapt them, reinterpreted them, and thereby to grow in wisdom, emotional and spiritual health, and resilience.

To make a start, let’s turn to an Augustinian trajectory running through Thomas Aquinas and Paul Ramsey, and finding its latest expression in the Oxford Theologian Nigel Biggar –from whose In Defence of War I will draw several primary points. It is from the Augustinian tradition that we can take our basic bearings that killing comes in different kinds (Aquanis). But not only from there. Positive law recognizes this in the distinctions it renders within the category of homicide: murder is a form of criminal homicide while other forms of homicide are not. Kudo, too, acknowledges distinctions. There is the ideal – “Thou shall not kill” – and there is what is practically required of him – “kill”. That he gives priority to what is required implies that he is allows for at least two species of killing: unnecessary and necessary. Whether these variants warrant for him varying moral judgments, or degrees of condemnation, is less clear. 

Along with the distinctions, the Augustinian will recognize common characteristics as well. For instance, whenever a person is killed evil results. To the Augustinian, evil is a privation of wholeness – the loss or diminishment of some essential good. Endorsing the privative view, Nigel Biggar observes that killing another human being is always to cause an evil because it deprives the victim of the good of life. He rightly presses this notion all the way down – applying it even to the killing of someone “who has let himself grow monstrously corrupt – think Hitler, Stalin, or Pol Pot.” That their death seems to involve the loss of nothing good is only because they have “so misdirected their lives that”, for most of the rest of us, their losing the good of life “amounts to a moral gain rather than a loss” (Biggar, 2013) So, to kill a person is always to cause an evil. But it is not always to do a wrong. Biggar explains:

History is sometimes very unkind to us and forces us into the position of not being able to do anything without becoming responsible – in some sense – for causing evil. I can kill you out of contemptuous hatred, intending nothing less than your annihilation, constrained by no necessity, and with no proportionate reason to prefer another’s life to yours. Or I can kill you without malice, with respectful and manifest reluctance, necessitated by love for others, and with sufficient reason to prefer their lives to yours (Biggar, 2013).

What is being maintained here is a distinction between non-moral evil and moral evil, or evil and wrongdoing respectively – with the consequence being only moral evil or wrongdoing is morally blameworthy. What accounts for the disjunction is the sad fact that there exists in our world “many practical conflict-situations where an evil can be avoided or a more or less necessary good achieved only when another evil is reluctantly caused” (McCormick, 1978). The removal of a child’s gangrened leg is an evil, it is the loss of essential goodness – that of bodily integrity and function. But if the deed is done by an honest surgeon with the aim of securing the health of the child-patient then no wrongdoing has occurred. In fact, it is a moral act; the surgeon is to be thanked and his skill, though not the necessity of employing it, to be celebrated. Contrast this with the sadist who steals into the sleeping child’s hospital room and recklessly chops away the gangrened leg for the perverse pleasure of it. It makes no difference that the leg was due for removal – the sadist’s carving is a moral evil, a wrongdoing, and a guilt-worthy act.[1] Clearly, intention matters and Biggar’s lament proves true: “While no one should want to cause evil or harm, the experience of finding oneself in the position of being morally obliged to mete it out is common enough” (Biggar, 2013). 

This brings us to the familiar nexus of the Christian doctrine of just war and the principle of double effect. Double effect is one means of analyzing complex, voluntary actions: “A human action,” Biggar tells us, “comprises ends and means, and is unintelligible apart from its intentional structure” Double effect distinguishes “an act’s effects into those that are intended and those that are foreseen but unintended…[it] makes the agent’s intention (or his negligence) an important criterion”(Biggar, 2013).

For Biggar, the reasons for this are several and good:

  1. “[Double effect] articulates the common intuition that, though their effects are the same, accidental homicide and murder should be distinguished in terms of intention.”
  2. It allows us to emphasis “the subjective, reflexive impact” of intending harm on the agent himself. “When we intend to harm, we identify ourselves with evil and thereby corrupt ourselves.”
  3. “While the human agent has relatively little control” over the parade of consequences that result from any singular action, whether he intends and enacts the action in the first place depends entirely on his own decision
  4. This is partly why intent should weigh more heavily than consequence in assessing the moral quality of an act
  5. “The growth of virtuous persons is itself a great good in the world”
  6. Intention matters because those actions which I intend today lead me to intend similar actions tomorrow – this is to say that moral habits tend to be habit forming
  7. This is more than merely instrumental: “virtuous activity has an intrinsic beauty that exhilarates the human heart.”
  8. “Finally, for Christians, and some other religious believers,” the habituation of virtue, cultivated in part by right intentions in moments of choice, “is a very great good since it is a condition of participation in the fullness of life beyond death (Biggar, 2013).

In light of the importance of intention in the moral analysis of an act, double effect makes a crucial distinction between the effects of an act that the agent intends and those the agent accepts with reluctance. Morally speaking, I may intend good effects (justice) and may only accept the evil effect (death) as an undesired accompaniment (Biggar, 2013). Biggar now inquires as to what exactly it means to intend something and asks how we know when an effect is intended versus merely accepted with reluctance. We can take as an example an action with ambiguous effects – say, the firing of a weapon that protects one person at the same moment that it kills another. I may choose to fire the weapon because I intend the effect of protection while I only accept the effect of killing with reluctance. However much I chose to take the lethal shot, the killing can remain entirely unwanted (Biggar, 2013). 

What this suggests is that intention is not simply whatever I choose to do but also something that correlates with desire – not just willing but wanting (Biggar, 2013). An effect that I intend, therefore, “is one that I both choose and want; and an effect that I only accept is one that I choose but do not want.” Here, Biggar presents a modest qualifier. Sometimes one intends what they do not (in a certain but real sense) actually want. What’s behind this is a competing set of different kinds of wanting. On the one hand, there is what he calls ‘rational’ wants – “the desire for what one knows to be good and to align oneself with it;” and, on the other, ‘sensual’ wants – the baser desire “to be in a state of physical and emotional satisfaction and to avoid what is painful.” Naturally, “what matters is that I should want rationally what is good and right, even if at the same time I do not want sensually what is painful” (Biggar, 2013). 

Now, for Biggar, double effect’s emphasis on intention does not mean that this is the only location of moral analysis. We are responsible for both what we intend as well as what we merely accept. Ascertaining whether our being responsible for causing evil means also that we are morally culpable hinges on our justification. Our account must demonstrate first, that our causing it could not have been avoided nor, second, that it was done in vain, in the sense that it subverts or destroys the very good that one had hoped to gain by it, and finally, that it is not disproportionate – it doesn’t outweigh the good achieved. If it is determined that an agent did, indeed, accept needless, vain, or disproportionate evil, then, “at the very least, he has been culpably negligent…and at worst he actually wanted the evil that he only pretended to accept reluctantly”(Biggar, 2013). 

To summarize Biggar’s proposal: 

If an act that causes foreseen evil (such as death) is to be morally justified, it is important that what is intended by it is something else, something good. However, while right intention is important, it is not sufficient. In addition, the evil must be accepted with an appropriate reluctance that manifests itself in serious attempts to avoid or minimize it – serious attempts to render its acceptance proportionate. But that, too, is not sufficient. In addition, the acceptance of proportionate evil must not offend against any strict [already existing] obligation (Biggar, 2013).

I now want to bring this conception of double effect to bear on Kudo’s belief that “killing is wrong but in war it is necessary.” If Biggar’s account is sustainable, then because the life of any human being is a good and his death an evil, warfighters should not actually intend either to wound or to kill. While it might be right to rationally desire to engage in a deliberate action that is likely to harm or kill an adversary, it can never be morally appropriate to sensually desire it. Quoting Biggar:

To do so would be to vitiate the agent’s heart and will, to corrupt his moral character, to jeopardize his fitness for life beyond death, and to increase the likelihood of his committing further malevolent harm in the world (Biggar, 2013).

In other words, it is to bring about many of the conditions endured by those who are suffering from moral injury. But I now suggest a caveat. Moral injury as a psychological construct is not making judgments about what are or are notlegitimate normative commitments. All that has to happen for one to suffer moral injury is that one acts in such as a way that they believe they have done or allowed to be done something that contravenes moral norms. But what if, as the principle of double effect suggests, they are wrong about the status of their normative commitments? What if it is permissible to choose to cause the death of a human being provided:

  1. “That what is intended is something other than his death (e.g. defending the innocent)? [the death is genuinely not desired propter se]
  2. “That the possibility (or even certainty) of his death is accepted with an appropriate and manifest reluctance?
  3. And that this acceptance is necessary, non-subversive, and proportionate?” (Biggar, 2013).

What if, “morally speaking, deliberately to cause death in this fashion is not the same as intending to kill?” (Biggar, 2013). One immediate upshot is that we now have conceptual resources to help sever the link between lawfully deployed lethal force and moral injury. Kudo might have been right after all: to properly wage war perhaps you do have to recalibrate your moral compass – just not in the way he first suspected.

Such recalibration returns us to the headwaters of the Christian realist patrimony. In identifying the true evils in war, Augustine fingers the desire for harming, the cruelty of avenging, an unruly and implacable animosity, the rage of rebellion, the lust of domination and the like (Augustine, 1887a). Positively, he mandates that the just warrior cherish “the spirit of the peacemaker” and recognize that it is necessity and not happy-desire which prompts the conscientious warrior to “slay the enemy who fights against” him (Augustine, 1887b). For Augustine, the use of violence is deployed against an enemy in order to punish him for his unjust aggressions with a sort of “kind harshness” that serves to constrain him, to prevent him from further wrongdoing, to confront him with his own injustice, and so to encourage him to repent and embrace peace (Augustine, 2001). 

Of course, even if such distinctions render conceptual clarity regarding killing in war, there still might be occasion for practical anxiety. Not everyone is as sanguine as Augustine that such purity of intention can walk the battlefield, of whether “the attitudinal expectations of the Christian tradition are realistic in the first place.” The doubt is partially grounded biographically. 

Let us return to Karl Marlantes. In his combat memoir, Marlantes recounts a ferocious assault up a steeply angled hill laced with a thick band of interconnected trenches. In attacking these defenses, Marlantes and several Marines found themselves involved in a deadly faceoff with the occupants of a fighting pit above them. A pair of NVA soldiers would pop-up in their hole and roll grenades down at the Marines. While the explosives were, for the moment, bouncing past the Marines and detonating harmlessly behind them, it wouldn’t be long before NVA got their timing right. 

Finally, the Marines managed to kill one of the occupants and while the survivor was pinned in his hole by suppressing fire, Marlantes was able to maneuver into a flanking position. He settled the stock of his rifle into his shoulder and waited for the enemy soldier to pop up again to throw his next grenade. Marlantes describes the moment:

Then he rose, grenade in hand. He was pulling the fuse. I could see blood running down his face from a head wound. He cocked his arm back to throw – and then he saw me looking at him across my rifle barrel. He stopped. He looked right at me. That’s where the image of his eyes was burned into my brain forever, right over the sights of my M-16. I remember hoping he wouldn’t throw his grenade. Maybe he’d throw it aside and raise his hands or something and I wouldn’t have to shoot him. But his lips snarled back and he threw it right at me (Marlantes, 2011).

As the grenade left his hand, Marlantes fired. The soldier was killed, and the grenade detonated harmlessly. When Marlantes asks himself what he felt back then, he answers: pleasure and satisfaction – he was alive! That felt good. Relief, no more grenades! Another obstacle was out of the way of achieving their mission, that felt good too. “But,” he admits, “it also felt just plain pleasurable to blast him…There is a primitive and savage joy in doing in your enemy.”

Now, however, Marlantes feels differently. Now he has the time to imagine the NVA soldier as one of his own sons. He sees him trapped, filled with fear as he battles against these huge Americans who charge “relentlessly from out of the jungle, swarming up the hill, killing his friends in their holes around him.” In his sensitized state, Marlantes envisions the boy’s final moments: wounded, knowing that “death is coming in a crummy little hole hundreds of miles from his family, and he has never made love to a woman and he will never know the joys and trials of a family of his own.” Marlantes asks, “My feelings now? Oh, the sadness. The sadness. And, oh, the grief of evil in the world to which I contributed.” He continues:

What is different between then and now is quite simply empathy. I can take the time, and I have the motivation, to actually feel what I did to another human being who was in a great many ways just like my own son. Back then I was operating under some sort of psychological mechanism that allow me to think of that teenager as “the enemy.” I killed him…and…moved on. I doubt I could have killed him realizing he was like my own son. I’d have fallen apart. This very likely would have led to my own death or the deaths of those I was leading (Marlantes, 2011).

It is with combat testimony such as this in hand that Martin Cook advances an uncomfortable conclusion regarding the attitudinal requirements of the Augustinian tradition:

It appears that the normative Christian tradition’s central idea that Christian soldiering is acceptable only if accompanied by a continual “spirit of a peacemaker” who approaches his distasteful task mournfully is fundamentally at variance with psychological possibility (Cook, 2013).

The assertion can be made even more uncomfortable. If Cook is right, then the Augustinian injunctions not only fail, but also serve, by making an already difficult job even harder, to add additional and unnecessary burdens to our warfighters. At best, the prescription of benevolent attitudinal requirements is a nasty, uncharitable charade. At worst, by amplifying the distance between what warfighters believe they ought to feel and what it is actually possible for them to feel, the normative tradition colludes in the cultivation of moral injury. It sets a normative standard which is impossible not to violate. 

But I want to suggest that Marlantes’ own testimony betrays his assertion that had he been aware of his love for that Vietnamese boy then, in the midst of combat, he never would have been able to kill him. Recall that after he and that boy locked eyes over the sights of his M-16, Marlantes hesitated. He hesitated long enough to hope the kid would not throw the grenade, that he might, instead, simply toss it harmlessly aside and raise his hands “or something” and he would not need to be shot. What is that seemingly naïve hope in the midst of combat? Is it not desiring that you might not have to do the terrible, and terribly necessary, thing when that necessary thing means bringing harm to the human being positioned against you? Is it not precisely what Simone Weil spoke of when she described that “interval of hesitation”(Weil, 2000)—  that luminous moment in the midst of raw, red, flesh-hewn conflict in which we comprehend the humanity of the other before us and, even as we might be in the very midst of the kill, we pause. If only for the barest of fleeting moments. In his interval of hesitation, what Marlantes did, and experienced, is, by my lights, love. He loved that boy. And then he killed him. And nothing in that is a contradiction. 

The proposal I have been advocating does not see a contradiction in hoping for peace but engaging in war, and even weeping over it after the fact. Granted, this image of the enemy requires the cultivation of a certain callousness, a thickening of the skin such as is required of the surgeon when cutting away limbs to save lives, or a parent when punishing an errant child. If everyday life furnishes us plenty of occasions in which we must thicken our skin to do the right thing despite painful – even destructive – side effects, how much more will a life in a combat zone? But callousness, like other forms of distancing, betrays itself. It makes plain that the calloused heart is the one that that, in fact, grasps the gravity of the present task. With a kind of peripatetic moderation, the calloused warfighter knows it must not be too easy, nor too hard, to make the necessary kill. 

But here I close with a note of caution. It is insufficient simply to assert—or even to prove—that moral injury is not a necessary result of killing in war. The stress is on the word necessary. There is a distinction to be made between the claim that moral injury is a necessary result of killing in war and that it is unavoidable. The former suggests that there is no possible world in which one can kill in war and be free of moral injury—because moral law insists that the effect of moral injury ought to follow the cause of having killed. I have been at pains to deny this. But it could be that there is a world—perhaps our own—in which killing in war does not necessitate moral injury, but in which moral injury is, essentially, unavoidable. 

Consider again our unfortunate motorist who accidentally killed the child. It is not necessary that he suffer moral injury—he has not violated a moral law. Nevertheless, as the driver of the car that struck the child, he knows himself to be the causal agent of the child’s death. Unless one were simply heartless, it seems essentially unavoidable that great—perhaps crippling—grief would follow.

To mitigate this, we might be wise to introduce a distinction between moral injury and what we can call moral bruising. Moral bruising can be taken to follow the same idea as physical bruising. That is, the bruise is a result of an impact trauma that falls short of a long-term, debilitating injury. I want to reserve moral injury for that justified trauma that comes from the guilt of having done something morally wrong. Moral bruising, however, we can posit as coming not from guilt but from grief, even the grief attending action that is morally right—as is lawful killing in a justified war—or morally neutral—as is accidental killing. 

Such a proposal, I submit, allows us to account, as Marlantes testifies, for the sorrow of combat. To see, as Marlantes saw, that the enemy is a fellow human being means that—at least in most circumstances—we ought never to rejoice in gettingto kill, but that we lament in having to. It is, perhaps, only in this way that it is possible both to recognize the humanity of the enemy and to kill again and again and again and yet not be a man of blood (John of Salisbury, 1990). 

Instead, it allows for the warfighter to justify the use of lethal force on grounds other than lesser (moral) evils. In disentangling the very business of warfighting from moral injury, we may begin to unburden warfighters from unnecessary burdens of guilt. At the very least, in distinguishing actions that issue in sorrow from those that issue in blame, we may uncover different sets of remedies to address different kinds of wounds. Thus, only thus, might it be possible to navigate the morally bruising theatre of war without becoming, oneself, morally injured.

Works Cited

Augustine (1887a). “Contra Faustum,” in Nicene and Post-Nicene Fathers, ed. Philip Schaff, trans. Richard Stothert, vol. 4 (Buffalo, NY: Christian Literature Publishing Co, 1887), XXII, Chap. 74.

Augustine (1887b).  “Letter 189, To Boniface,” in Nicene and Post-Nicene Fathers, ed. Philip Schaff, trans. J.G. Cunningham, vol. 1 (Buffalo, NY: Christian Literature Publishing Co, 1887).

Augustine (2001). “Letter 138 (to Marcellinus),” in Political Writings, ed. E. Margaret Atkins and Robert Dodaro (Cambridge: Cambridge University Press, 2001).

Aquanis, Thomas.  Summa Theologiæ, n.d., II–II, Q. 64; and Augustine, Questiones in Heptateuchem, VI, 10;  Contra Faustom, XXII, 74; De Lib. Arbit., I, 4.9; 5.11-5.12.

Biggar, Nigel (2013). In Defence of War (Oxford: Oxford Univ. Press, 2013), 92.

Cook, Martin L. (2013). Issues in Military Ethics (State University of New York Press, 2013), 115.

John of Salibury (1990).  Policraticus, trans. Cary J Nederman (Cambridge; New York: Cambridge University Press, 1990), 31.

Kudo, Timothy (2013). “I Killed People in Afghanistan: Was I Right or Wrong?” in the Washington Post, dated January 25, 2013, and testimony in Pauline Jelinek’s “I’m a Monster: Veterans ‘Alone’ in their Guilt,” Associated Press, February 22, 2013.

Litz, Brett T. et al (2009).  “Moral Injury and Moral Repair in War Veterans: A Preliminary Model and Intervention Strategy,” Clinical Psychology Review 29, no. 8 (December 2009): 697. 

Marlantes, Karl (2011). What It Is like to Go to War (New York: Grove Press, 2011), xi.

Maguen, Shira et al. (2012, 2016). “Killing in Combat May Be Independently Associated with Suicidal Ideation,” Depression & Anxiety (1091-4269) 29, no. 11 (November 2012): 918, and: Shira Maguen et al., “Veterans’ Perspectives on the Psychosocial Impact of Killing in War,” The Counseling Psychologist 44, no. 7 (2016).

McCormick, Richard A. and Paul Ramsey, eds. (1978). Doing Evil to Achieve Good: Moral Choice in Conflict Situations (Chicago: Loyola University Press, 1978), 7.

Weil, Simone (2000). “The Iliad or The Poem of Force,” in Simone Weil: An Anthology, ed. Siân Miles (Grove Press, 2000), 174.