I was not a Christian when I joined the Marine Corps. I was not a Christian when I deployed to Afghanistan, nor when I returned home. I entered the Church only after I had left the Marines. This has made my thoughts about the relationship between military service and Christian faith oddly disjointed. Not only have I entered the Church since leaving military service; I’ve also become a professor of theology. The disjunction between my life in the Marines and my life as a Catholic theologian allows for—perhaps “demands” is a better word—a kind of reflection on war not immediately available to everyone.

Like many veterans, I found myself more emotionally involved in this past summer’s rapid evacuation of Afghanistan than I thought I’d be. It’s been over a decade since I returned home from the war, but watching the final defeat and withdrawal of U.S. forces from a country where I spent a year of my life was distressing. It helped crystallize thoughts that had been foggy and inchoate. The violent collapse of our two-decade mission in Afghanistan has made it clear to me that the Church needs to recover a theology of sin and a penitential practice capable of accounting for the trauma of war. Calls for prayer, reflexively saying “thank you for your service,” singing patriotic hymns on Memorial and Veterans Day weekends—these aren’t the answer. At best, such gestures make the Church seem generally uninterested in war and its consequences. At worst, they conform the Church’s response to that of the world, in the Pauline sense of that term. Shouldn’t the patriotism of the person who knows her true homeland is not of this world be distinguishable from the civil religion of the United States?

The Church has resources for addressing these questions. Some of them will likely make you uncomfortable—as they do me. But we all have good reason to feel uncomfortable. The end of the war in Afghanistan ought to elicit introspection and compunction, and the Church’s penitential practices are, for Catholics, the most suitable expression of that compunction. Now is a good time for us to examine our consciences, individually and collectively.

Returning from Afghanistan was a stranger experience than going. A seasoned master gunnery sergeant told me it would be: “Nothing you do when you get back will seem as important as this, and you’re going to have to get used to that.” He was right, of course. The stakes of everyday life are less extreme. Decisions are not usually life-and-death. There are more mundane details to civilian life—buying groceries, paying bills, renewing your car registration—than you remember. This adds up to things seeming less important. But it’s his warning that I’d have to get used to it that sticks with me. His point wasn’t that ordinary experiences are less important, but that they seem so. Getting used to that means coming to terms with your time at war.

Much of this happens within your unit. Some of it happens with your friends and family, some with the broader community. Your interactions with all of these people helps you understand what it means to have gone to war and to have returned. The Church has a role to play here, too. One thing the Church does, which distinguishes it from all the others, is provide access to the sacrament of Reconciliation. Those returning home from deployment often have things to confess—sometimes terrible things. The ministry of the Church is there as a means of God’s grace, to deal with sin. But what if that’s not enough?

I don’t mean that the grace of the sacrament isn’t enough. I mean that the Church might not be able to wait passively for penitents to come to the sacrament for healing. One reason the Church can’t stand by and wait is the deep cultural narrative about military service in the United States. According to that narrative, those who serve in uniform are heroes. We must support the troops. What the troops are up to usually isn’t part of the discussion. The thing to do—the only thing to do—is support them.

The roots of this unreflective support are pretty dark. The backdrop of “thank you for your service” is the complete failure of Americans during the Vietnam era to welcome and assist returning troops. I’ll never forget the people waiting to welcome my unit home when we set foot on American soil after a year away. Many of them were Vietnam veterans whose own homecomings had been decidedly different from ours. The veterans waiting for us when my unit stepped off the plane recognized the need—their own and ours—to be seen, and to be seen as honorable. Better, we’ve decided (and it surely is better) to reflexively support those fighting the nation’s wars, to pat them on the back, to call them heroes, than to vilify or ignore them.

But neither vilifying veterans nor heroizing them will help them come home well. Neither helps them come to terms with their actions during deployment. This is where the Church has the tools, and the responsibility, to take action. It can do so by demanding penance from those who have returned from war. To demand penance is not to demonize. Rather, it amounts to an acknowledgment that “evils and injustices accompany all war” (the Catechism of the Catholic Church, §2307). War, as the Second Vatican Council tells us, is something we’re enslaved to, something from which we should desire to be freed.

The necessity for universal penance after war turns on a recognition that bloodshed is evidence of sin, of deep brokenness that needs specific attention. Penance can certainly be related to personal sins, and often should be. But we can identify broader reasons for adopting penitential disciplines. Job, “a blameless and upright man” (Job 1:8), adopts the posture of a penitent when he shaves his head and sits on the ash heap. He does so not as penance for his own personal sin, but to lament the common human condition after the Fall.

In his August 29 Angelus message, Pope Francis called on all of us to fast and pray for the people of Afghanistan. He said, “I address an appeal, to everyone, to intensify your prayer and practice fasting. Prayer and fasting, prayer and penance. This is the moment to do so.” Because this was a call to everyone, it included those culpable for wrongdoing in Afghanistan. But it also included many people with no obvious connection to that country. Here, in other words, is an application of penitential discipline to people who have not committed any personal sin.

The work of penance is salutary. It goes to work on the source of grave evil, the human heart. Penance, and ascetic disciplines generally, are meant to bring us into confrontation with ourselves. As St. Gregory the Great puts it, “When we attentively consider our darkness and blindness, we are mentally provoked to tears.” These tears, Gregory insists, are a necessary step toward joy: “The soul sighs before it eats.” Before we’re capable of making spiritual progress, we must be ready to confront ourselves, to be lanced by compunction. This view of penance requires us to speak of sin not just as a particular action, but as an affliction. Sin, St. Paul tells us, is something that reigns (Romans 5:21), enslaves us (Romans 6:9), leads to death (Romans 6:16), and dwells in us (Romans 7:23). If our talk about sin is focused exclusively on personal actions and neglects the way sin infects and corrupts us, the range of things for which we might do penance will be too narrowly circumscribed. Sin is something from which we need to be delivered, not something we can simply avoid. Nothing drives this reality home as acutely as war.

This is not to downplay the moral challenges faced by the individual soldier who has sinned on the battlefield. Some will return from a conflict bearing serious personal guilt. In this case, neither heroization nor demonization will provide the medicine that a wounded soul needs. Demonizing the returning soldiers can drive them to despair, to conclude that Christ’s forgiveness is not available to them. Heroizing soldiers causes the opposite but equally damaging problem: presumption. Even if a returning soldier is aware of his or her guilt, being greeted as a hero is likely to cause some cognitive dissonance: Am I wrong to feel bad about what I’ve done if people are praising and thanking me for it?

The Church needs to act as a physician for those returning from war by calling on them to do penance. In the case of those guilty of personal sins in the conduct of war, this call is salutary. Unlike those caught in despair or presumption, the penitent is able to recognize the spiritual wound sin causes and to receive the salve of forgiveness. The imposition of penance forces an examination of conscience. Some who have gone to war and returned home have never felt the need for forgiveness—not because they haven’t sinned but because they’ve yet to recognize their sin. This might be through lack of attention, or it might be through self-deception. In either case, the call to do penance can spur the returning soldier’s conscience, and then provide a remedy for whatever guilt he or she may feel.

This is something the Church ought to know how to do. The imposition of penances on soldiers was a normal practice in the Middle Ages. You can see an example of this in the Ermenfrid penitential, promulgated after the Battle of Hastings. The ordinance allocating particular penances to those who took part in the fighting provides very specific guidance. A soldier received one year’s penance for each man he knowingly killed, forty days for each man he wounded. This public penitential discipline likely amounted to exclusion from Communion and a diet of bread and water for the prescribed period.

Nor was it only the number of people killed or wounded that was taken into account. One’s intentions also mattered. Fighting and killing for personal gain required the full seven years of penance standard in the case of homicide. But even those who fought in service of their sovereign for what they deemed a legitimate cause, and with no consideration of personal gain, owed three years of penance. In short, it was understood that there were better and worse reasons to go to war, but no matter the reason some penance was always required. This, too, suggests that the Church was concerned not only about the particular actions of individuals but also about the corrupting effects of sin that are abundantly evident in times of war.

This view—that participation in war called for penance—finds support not only in the penitentials that issued penances to soldiers. Hrabanus Maurus, Burchard of Worms, and Peter Damian all insisted on the need for public penance for those who participate in warfare. And no less a personage than Gregory VII, the great reform-minded pope, called the profession of arms one “which could not be engaged in without sin.” This view recognizes that the conditions of warfare are at once the product of sin and the near occasion for sin. War tends to coarsen those who take part in it. As Thomas Aquinas puts it, “warlike pursuits are full of unrest,” and hinder the contemplation of God. But that unrest does us harm in another way when it incites us to violence and hatred.

My own time in Afghanistan brought me face to face with the coarsening I’ve just described. Most of my time in-country wasn’t spent on patrol or in firefights, but on trying to locate specific people so that they could be captured or killed (mostly killed) by conventional forces, special forces, or drone strikes. You get to know a lot about the specific people you’re after. You might think this would breed empathy or understanding. In my case, it didn’t. The time you spend, day in and day out, tracking people whose deaths you hope will contribute to the overall success of the mission leads to dehumanization. Once you’ve settled into a rhythm, the procedures you’ve put in place make your work relatively mechanical. What information do we have on this target? Where will he be tomorrow? Who’s he likely to be with? What’s the expected impact of killing him? You get used to asking these questions. And at such a remove, the impact of the work you’re doing—the spiritual toll it takes—isn’t immediately obvious. It’s there, though.

These effects are much more obvious to those whose jobs require them to stare death in the face, their own and others’. Phil Klay’s book Redeployment presents these effects in stark detail, with a realism that is hard to bear. If you’re trying to understand what I mean by the effects of the War on Terror, his book is a good place to start. We know, too, from the after-effects of war, that not all wounds are physical. The military has gotten better at recognizing and treating the psychological damage suffered in combat. The Church needs to make similar progress in recognizing the spiritual injuries soldiers come home with.

More than four times as many service members have died by suicide than have died on the battlefield since the beginning of the post–9/11 wars. One way to help soldiers to come home is to treat their wounds—physical, psychological, or spiritual. Jesus Christ is the physician of souls, the one capable of binding up all wounds. In order to bring the healing available in Christ to those returning from war, the Church should impose penances on them. In this way, the Church will stand opposed to the evils of violence and hatred that pervade all warfare. It will help all veterans learn to weep for our common condition, force an examination of conscience, and extend the offer of Christ’s peace, both to those who know they need it and those who don’t.

But too narrow a focus on veterans can obscure the fact that the citizens of the United States are collectively responsible for the war and its many failures. We’re responsible because sovereignty in this nation is derived from the will of the people. This includes both our willingness to wage an unjust war and our unwillingness to end it for the past two decades. Sins of commission and omission abound.

Christians have tools with which to reflect on the justice of war. But if the just-war tradition is to be more than just a device for rationalizing bloodshed, then we have to be prepared for critical self-evaluation—for a national examination of conscience. Christians must ask themselves whether the war in Afghanistan met the standards the Church has established both for going to war (jus ad bellum) and for the conduct of war (jus in bello). I am not a pacifist. I think there are circumstances in which the use of force is necessary and just. But we need to remember that the Christian understanding of just war begins with a bias for peace. Not only are the standards for waging a just war high; the purpose of the war itself must always be the re-establishment of peace.

It’s clear to me that the war in Afghanistan—and a fortiori the war in Iraq—failed to meet the Church’s criteria both for going to war in the first place and for waging it justly. I’m drawing these criteria from the USCCB’s 1983 document “The Challenge of Peace,” which presents the conceptual apparatus of just-war theory in a straightforward manner. It’s evident that the Afghan war failed to meet the just-war criteria of last resort, probability of success, and proportionality.

First, the war in Afghanistan was not a war of last resort. Though the events on 9/11 demanded a response, that response need not have been war. The speed with which the United States found itself in an ever-expanding conflict means that all other means for addressing the problem could not have been exhausted—not on that timeline. The United States had been attacked, and at least part of the reason for the immediate and overwhelming military response to the attack was the need to be seen to be doing something about it. But even if we assume that the United States had exhausted all other options, which seems exceedingly unlikely, two additional criteria were either ignored or abandoned.

Probability of success and proportionality are both crucial components of just-war analysis. To assess this probability of success you’d first need to have fixed criteria for success: What is the desired end state? What would victory look like? The answer to these questions was constantly changing for the duration of the war in Afghanistan. First the goal was to eliminate the threat of Osama bin Laden, then it was to remove a hardline Islamist government, then to contain Iranian influence in the region, then to provide opportunities for women, then to build a stable democratic government, then to train and equip military forces. We were never quite sure what we were doing there. And without being sure of one’s aims, it’s impossible to estimate the probability of success.

But even with the most general and generous view of what might count as victory in Afghanistan, there was another reason to doubt the probability of success: the historical track record. The Macedonians, the British, and the Russians all failed to conquer Afghanistan. Did we have good reason to believe that we would succeed where others had failed? Had the conditions in Afghanistan changed significantly since the last time the Afghan people had defeated a major superpower? Shouldn’t we have expected a protracted guerilla war, with the Afghans receiving weapons and materiel from our international rivals? Again, as the mission in Afghanistan rapidly ballooned out of control, it became evident that we’d bitten off more than we could chew. But even the most basic historical consciousness would have led a reasonable person to conclude, before the war had started, that anything describable as victory was unlikely.

Even more obvious than our failure to meet the just-war criteria of last resort and probability of success, however, was our massive failure to satisfy the condition of proportionality. Here it’s necessary to think not only of the justice or injustice of going to war in Afghanistan but also of how the war was waged. Nearly 3,000 people were killed by the terrorist attacks on 9/11. It was a staggering blow to the nation, a tragic, hateful thing. But the U.S. response to this has resulted in a death toll orders of magnitude higher. The Watson Institute at Brown University estimates the number of deaths caused by the war in Afghanistan at around 176,000. That number includes 53,000 opposition fighters and 46,319 Afghan civilians. The number of Afghan civilians killed by coalition airstrikes—about 5,900—is nearly twice the toll of 9/11. These are just the numbers for Afghanistan; there were even more deaths in Iraq. This also doesn’t take into account the tens of millions of people who have been wounded or displaced in both countries.

In short, these wars were not just. Nor can our collective responsibility for them be shrugged off. It’s something we need to reckon with. And once again, it’s instructive to look at the Church’s past to see how we might do that. St. Ambrose, upon hearing that the emperor Theodosius had massacred the people of Thessalonica, refused to admit him to Communion until he did public penance. Theodosius had committed a grave injustice, killing thousands of men, women, and children. Ambrose demanded penance because Theodosius’s actions contradicted his baptism. They placed him outside Christ’s body, in a state of rebellion against God’s justice. For him to return to the fold required not only acknowledgement of his wrongdoing, but contrition and expiation.

This is where we Americans now find ourselves. We’re in a situation comparable to that of Theodosius. It cannot be the case that shifting sovereignty from one man to all citizens old enough to vote simply extinguishes moral responsibility. We should recognize our complicity in the injustices committed by our elected leaders on our behalf. But just as it wasn’t enough for Theodosius to acknowledge the injustice of his actions at Thessalonica, neither is the mere acknowledgment of our own guilt enough for us. What’s called for is contrition and expiation. We need to do penance. Just as the Church should impose penances on those who’ve returned from war, it should also recognize the corporate guilt of the country that sent them. Like the people of Nineveh who hear Jonah and believe in God, we need a prophetic voice to warn us so that we might all “call out mightily to God” (Jonah 3:8) in repentance. That voice should be the voice of the Church.

The injustice of America’s recent wars poses a pastoral challenge to our nation’s bishops. I’ve argued that our shepherds should institute penances for returning troops. But it’s reasonable to ask how American bishops should teach about military service in general. Would it be fair to tell troops only after the fact that they must do penance for their time at war? The bishops may need to do that now; the shot has been fired, so to speak. But in the future? An adequate pastoral policy would involve informing young men and women of the hazards—bodily, mental, and spiritual—of military service. If it’s true that, as Pope Francis teaches in Fratelli tutti, “We can no longer think of war as a solution, because its risks will probably always be greater than its supposed benefits,” then American Catholics should hear this from the pulpit. American Catholics might need to reconsider military service in light of their country’s recent record of waging unjust wars that devastate innocent civilians as well as combatants. This record remains difficult for me, as a veteran and an American, to confront.

If the Church has a responsibility to demand penance not only of veterans but of all U.S. citizens for their respective roles in the war in Afghanistan, what shape should that penance take? Why not start with the traditional penitential practices: fasting, almsgiving, and prayer. Specifically, the Church could provide returning veterans with catechetical instruction about praying the penitential psalms and participating in the sacrament of Reconciliation. It could impose a reasonable but serious period of fasting and involve returning veterans in the life of their parish communities. A parish with veterans who have recently returned from war might take the opportunity to join them in penance, to recognize a shared culpability, to “bear one another’s burdens, and so fulfill the law of Christ” (Galatians 6:2). This would be far more appropriate—and surely far more pleasing to the Lord—than another round of patriotic hymns.

This essay was first published in January 2022.