By Mathias Risse, Harvard University
The views expressed below are those of the author and do not necessarily reflect those of the Carr-Ryan Center for Human Rights or Harvard Kennedy School. These perspectives have been presented to encourage debate on important public policy challenges.
"Men who take up arms against one another in public war do not cease on this account to be moral beings, responsible to one another and to God."
— Lieber Code, Article 15
1. A Misguided War under Myopic and Immoral Leadership
As of mid-March 2026, the trajectory of America’s war against Iran—"Epic Fury”—remains deeply uncertain. While the superior might of American and Israeli forces can dismantle much of Iran's capacity to threaten its neighbors, regime change is far more elusive. After nearly half a century in power, the Mullahs’ regime and its security wing, the Revolutionary Guards, have literally nowhere to go once they lose power. Given what they have done to the Iranian people, they cannot even count on physical survival outside of power. Nor is the Iranian regime a one-man authoritarian operation; it is a deep institutional structure with well-developed succession procedures. Moreover, the Strait of Hormuz—that critical chokepoint for global oil and gas supplies—can be rendered impassable by a handful of cheap drones.
The combination of these three factors would have indicated all along that whatever problems Iran poses are unlikely to be ultimately resolved by military means. Reasonable people might disagree on this. So it is worth emphasizing that my assessment of Pete Hegseth’s role in American public life would stand up even if my strategic assessment were wrong. It also stands up even though, of course, the Iranian regime is a human rights offender at a considerable scale, a matter on which the Carr-Ryan Center and the Institute of Politics at the Harvard Kennedy School just held an event some weeks ago (also see here and here.)
In any event, it is against this background that the Secretary of Defense’s escalating rhetorical belligerence is so dramatically out of touch with any sober strategic analysis of the situation in the Persian Gulf. Inevitably, things go wrong in war. There could be no starker illustration of that basic truth than the destruction of an Iranian elementary school during the opening hours of the conflict—an incident likely caused by an American missile strike. The destruction of the school, which coincided with an attack on an adjacent naval base, killed about 175 civilians, mostly children, according to Iranian officials.
And yet Hegseth has made contempt for what he calls "stupid rules of engagement" a central component of his political identity. Such rules exist, among other reasons, to limit civilian casualties. He has boasted of unleashing the military to use “maximum authorities on the battlefield.” "Our rules of engagement," he declared at a briefing four days after the war started, "are designed to unleash American power, not shackle it." His slogans—"maximum lethality, not tepid legality"; "violent effect, not politically correct"—treat legal and moral constraints as obstacles rather than as integral elements of honorable soldiering.
One fundamental insight from the long history of reflection on the morality of warfare is that this is a domain where ethics and long-term prudence tend to converge. It can easily happen in human affairs that the right thing to do conflicts with self-interest. In war, however, adhering to rules that treat all participants—including, and especially, one's opponents—as human beings is also a matter of at least long-term prudence. Such rules limit lasting grievances, carry beneficial reputational effects, and sustain soldiers' sense that they are fighting for something more than the execution of an “epic fury."
In war, however, adhering to rules that treat all participants—including, and especially, one's opponents—as human beings is also a matter of at least long-term prudence.
In short, what we are witnessing is a war waged in a context where military force cannot resolve the underlying issues, but where excessive military action will sow pain and anger for generations, undermine American credibility in the world, and might well leave American soldiers increasingly doubtful about what they are actually being asked to do. In the United States, few people enlist with the intention of bombing children. Few sign up for "epic fury." Hegseth's leadership is not only immoral but profoundly myopic.
Reflection on the morality of war has deep roots in the Western tradition to which the Trump administration so regularly claims special allegiance (though it should not). Just war thinking is no "woke" innovation; it arose from the Christian foundations of the Western world. In the modern era, it was an American contribution that proved visionary and foundational to the renewal of what is, in fact, an ancient project. Hegseth has placed himself dramatically outside that tradition, betraying its legacy while simultaneously generating the very strategic problems that legacy was designed to prevent. Developing this point is the purpose of this commentary.
Much is happening in the world, and much of my overall commentary here has been concerned with making sense of Trump’s America. But even within that larger framework the outlandishness of Hegseth’s rhetoric and posturing—and the stunning extent to which it lies outside of the intellectual accomplishments of the Western and American tradition—is worth emphasizing.
It is appropriate to worry about the erosion of the American military soul, and, of course, it is apt to worry about the enormous damage that will be done to the world as a whole and to American security in particular if Hegseth has his way—that is, if he finds a way of translating his tough talk into actual guidance for the troops. Since much of what this administration does is spectacle rather than policy, it is far from clear that this rhetoric was ever meant to become operational doctrine. But that cannot reassure us. (See earlier comment on the possible end of universalism.)
2. Some Remarks on the Education of Pete Hegseth and His Comments on Harvard
Before examining that Western and distinctly American legacy in detail, it is worth noting something about Hegseth's own educational background at Harvard. While still working for Fox News, in June 2022, Hegseth made quite a show of tearing apart his Harvard diploma on live television. More recently, in February 2026, as Secretary of Defense, he severed all ties between the American military and Harvard. Both gestures seemed to convey the same message: that too much critical thinking about the United States goes on at Harvard generally, and at the Harvard Kennedy School in particular.
For Hegseth, we should note, critical thinking about the U.S. tends to be associated with “Marxism” and “racism,” the kind of racism practiced by those who do not appreciate critical attention to the role race has played in American history. That is, he tends to equate critical thinking about the American political system with opponents to the system, a phenomenon I have called vindictive tolerance.
I regret the Secretary’s decision to sever ties with Harvard deeply. Over many years I have found military personnel to be exceptional students who greatly enrich the life of the school—who frequently challenged the views of others and who, by their own account, benefited greatly from being challenged in return. Since its founding, the Harvard Kennedy School has taught thousands of service members and veterans.
This year alone, roughly 8% of our students have a U.S. military affiliation. Over the past ten years, more than 500 U.S. active duty, reservists, and veterans have enrolled in our various degree programs. Not a semester has gone by since I came to this school, in 2002, when I did not have military personnel in my own classes.
I would also like to mention that, this year, we launched the American Service Fellowship — a new initiative that will provide full scholarships for at least 50 public servants and military veterans to enroll next fall for a one-year, fully funded Master’s degree. It is the largest scholarship program in school history. (We also have several other funding opportunities for veterans and active-duty military members, such as the Pat Tillman Scholars and the Center for Public Leadership’s Military and Veteran Graduate Fellowship.)
Our Executive Education programs also draw military participants, including the Senior Executives in National and International Security program. Since 2001, we have trained over 5,000 active-duty participants. I am proud to say that I have been involved in quite a number of these programs as instructor or program chair.
I am sure most of these students with a military background would reject Hegseth’s accusation that Harvard attempted to indoctrinate them. Even those who thought we did would probably reply, with some pride, that they more than could hold their own against a bunch of lefties, and that being able to prove their mettle this way made them better at their job. They have always given their respective Secretary of Defense reason to be proud of them.
One of Hegseth's predecessors as Secretary of Defense, Ash Carter, spent much of his career at the Harvard Kennedy School. Carter—whom I greatly appreciated as a colleague, a relationship I have good reason to believe was mutual—was serving as director of our Belfer Center for Science and International Affairs at the time of his death in 2022. A center long known as a hub for productive engagement between the military and academia, Belfer also runs the National Security Fellowship for U.S. military officers and intelligence professionals—a fellowship for U.S. military officers who are eligible for senior development education and equivalent civilian officials from the Intelligence Community.
The Carr-Ryan Center too (then just Carr) has done important work with the U.S. Army on mass atrocity prevention and response. Over the three years that Sarah Sewall was Acting Director, between 2006 and 2009, that set of issues was central to the center’s programming.
I am hopeful, and confident, that once the Hegseth era has passed, the partnership between Harvard, and especially the Harvard Kennedy School, and the American military will be restored. It is fair to say that, outside military academies, no other university has had deeper ties with the American military than Harvard. For instance, aside from the Army and Navy service academies, Harvard has more Medal of Honor recipients (18) than any other U.S. institution of higher education. (Also see here.) Harvard’s relationship with the United States is as old as the United States.
What deserves most attention here is that during Hegseth's time at the Kennedy School, the just war tradition was a distinctive presence in the curriculum. What I am about to discuss—and in particular how deeply the morality of warfare is embedded in the Western tradition—is something Hegseth could readily have encountered in his own studies.
During those years, Bryan Hehir, one of the most prominent representatives of the just war tradition in American Catholic thought, was a faculty member there, as was Frances Kamm, one of the major philosophical contributors to the contemporary ethics of war.
This tradition was available to him. He chose either not to engage with it or to reject it, which tells us something about the choices he is making now.
3. On the Roman and Christian Origins of Just War Theory
"Just war theory" is the body of philosophical work that underlies humanitarian law as it has developed since the late nineteenth century. It reaches back to Roman antiquity but came fully into its own once Christianity had become the religion of the Roman Empire.
Before the rise of Christianity, Roman thinkers—Cicero above all—had already articulated certain restraints on warfare: that war should be formally declared, have a just cause, aim at peace, and avoid treachery. Greek and biblical texts also contain ideas about legitimate versus illegitimate violence, but no systematic theory had yet emerged.
It was Augustine, in the fifth century AD, who first wove these strands into a coherent Christian framework for when war can be just. In scattered passages across the City of God, his letters, and his sermons, he established three foundational pillars. First, war can sometimes be morally permissible when it is ordered in pursuit of peace or justice. Second, even a just war cannot be initiated or conducted by just anyone: it requires right authority, that is, authority exercised by properly accredited leaders. Third, Augustine insisted that just cause and rightful authority alone are insufficient: there must also be right intention. War must not be waged in a spirit of hatred or cruelty; its aim must be the restoration of order, not vengeance.
In other words, "epic fury" would never have qualified as right intention—even had the cause been just and the authority legitimate.
Christianity urgently needed a theory of just warfare after it had gradually come to dominate the Roman Empire. By the fourth century the Empire was Christian, and thus committed to a religion of the dispossessed that was animated by maxims of non-violence.
But what was to be done about the relentless incursions of Germanic warriors from the north? Was the Empire simply to absorb their assaults?
It was in response to this challenge that a governing doctrine became necessary—one that could guide the military conduct of Christian leadership and reconcile Christian faith with imperial responsibility. Michael Walzer's 1977 book Just and Unjust Wars remains an excellent contemporary introduction to this tradition.
Later thinkers developed and systematized Augustine's insights. In the 12th century, Gratian and the canon lawyers began organizing scattered texts into legal-theological doctrine. In the 13th century, Thomas Aquinas famously crystallized the classic three conditions in Summa Theologiae II–II, q. 40, drawing directly on Augustine: just cause, legitimate authority, and right intention. Later scholastics—Vitoria, Suárez, and others—elaborated further rules about proportionality, the protection of innocents, and the important distinction between criteria governing the resort to war and norms governing conduct within it.
The central point bears emphasis: as a religion of love, Christianity inherently requires something like a just war doctrine if it is also to govern. Hegseth's performative belligerence places him entirely outside this tradition. It also reveals that, unlike the formative thinkers of the Christian intellectual heritage to which he so frequently pledges allegiance—including in the very act of tearing apart his Harvard diploma—he has not grasped just why Christianity so badly needs such a doctrine in the first place. (And let me say again: there were classes on this at the Harvard Kennedy School when he attended.)
Setting aside absolute pacifist traditions (e.g., Quakers, Mennonites), there is no mainstream strand of Christian thought that rejects the necessity of just war thinking as a way of constraining war. There is no framework within that tradition capable of accommodating "epic fury."
Setting aside absolute pacifist traditions (e.g., Quakers, Mennonites), there is no mainstream strand of Christian thought that rejects the necessity of just war thinking as a way of constraining war. There is no framework within that tradition capable of accommodating "epic fury." One would need to start talking about Christianity in the context of providential nationalism or of America as a chosen nation with a divine mandate that would then license even this kind of fury. Maybe that is just what we learn here about Hegseth’s convictions.
And to be clear: such strands do exist in American history, but they have constantly been contested from within Christianity itself. After all, this would not be a Christianity that brings a message of love for everyone. It would be something completely different, and it would be unlikely to be the kind of Christianity that would appeal to most American Christians.
4. Just War Thinking in the American Tradition: The Lieber Code and Beyond
The United States has played a foundational, if often conflicted, role in the development of modern international humanitarian law (IHL)—the body of rules that seeks to limit the cruelty of war. From the Lieber Code during the Civil War to its central role in the Hague and Geneva regimes after 1945, the U.S. helped construct a legal and moral vocabulary insisting that war must be constrained by law and humanity.
The American chapter of this story begins in 1863 with General Orders No. 100, better known as the Lieber Code. Drafted for President Lincoln's administration by the German-American scholar Francis (Franz) Lieber, it was issued as binding instructions "for the Government of Armies of the United States in the Field" during the Civil War.
Three features are especially important.
First, the Lieber Code systematized the "laws and customs of war" in a manner no state had previously attempted. It addressed the treatment of prisoners of war, the status of irregular fighters, the protection of civilians and property, restrictions on pillage and devastation, limits on retaliation, and prohibitions on certain forms of cruelty. Its governing idea was that "military necessity" is real and sometimes harsh—but never a blank check.
Second, the Code was explicitly moral as well as legal. War is described as a brutal clash of armed forces, yet Lieber insists that "the more humane civilizations of the present day" accept restraints even when they could safely discard them. The Code thus helped entrench core IHL principles: the distinction between combatants and noncombatants, proportionality, and the rejection of torture and wanton suffering.
And third, it was unapologetically practical. This was not a philosopher's treatise but a field manual intended to guide Union commanders in the field—an early example of something the American military would later become known for: translating abstract norms into operational doctrine.
In this sense, the United States did not merely adopt humanitarian law; it authored one of its first modern, comprehensive statements. It is a profound irony that the same country now has a Secretary of Defense who derides "tepid legality" and elevates "maximum lethality" as the primary measure of military success.
Lieber's ideas did not remain confined to the Civil War. European militaries and jurists studied the Code carefully, and its structure and concepts influenced subsequent international codifications—most notably the Hague Regulations of 1899 and 1907 governing the laws and customs of war on land. The United States participated in those conferences and thereby helped internationalize what had begun as a national doctrine.
The Geneva tradition—initially focused on the wounded and on medical services—was driven by Henry Dunant and European states, but the United States joined early and became increasingly central in the twentieth century. After the devastation of the Second World War, the U.S. was a key architect and champion of the 1949 Geneva Conventions, which extended protections to prisoners of war and civilians and codified core IHL principles on a global scale.
The U.S. was also instrumental in the postwar tribunals at Nuremberg and Tokyo, where American prosecutors and judges played a central role in defining "war crimes" and "crimes against humanity" as offenses for which individuals could be held personally responsible.
5. Back to Hegseth
To be sure, the American record in this domain is deeply ambivalent. The U.S. has at times declined to ratify more restrictive IHL instruments, or has attached reservations and narrow interpretations to those it did accept. Episodes from Vietnam to the "war on terror" have illustrated how far practice can diverge from principle: My Lai, extraordinary rendition, Abu Ghraib, black sites, and contested drone strikes each placed severe strain on America's self-image as a law-abiding military power.
In fact, Canadian Prime Minister Mark Carney gave a speech at Davos in January 2026 in which he drew attention to the sheer range of ambivalences in American political practice and their consequences for world order.
Yet notice the structure of such earlier debates. Critics and defenders alike have argued in humanitarian-law terms: Was this compatible with Geneva? Did the rules of engagement respect the principles of distinction and proportionality? Are captured fighters "unlawful combatants" or prisoners of war? That very vocabulary is a legacy of the tradition the United States helped create. And that commitment has amounted to considerably more than the mere hypocrisy of vice paying a compliment to virtue—it has shaped institutions, constrained conduct, and kept accountability possible.
It is within this historical frame that Hegseth's posture becomes especially striking.
After the Second World War, the United States symbolically and institutionally embraced the idea that its armed forces exist for defense, not conquest. This was part of a broader shift in 20th-century thinking that sought to outlaw aggressive warfare altogether—a genuine historical innovation—and to restrict legitimate warfare to self-defense or collective security.
The National Security Act of 1947 and its 1949 amendments abolished the Department of War and created the Department of Defense, integrating the services under a single civilian secretary. This terminological shift accomplished several things at once. It reflected the UN Charter's prohibition of aggressive war and the new principle that force is legitimate only in self-defense or pursuant to collective security. It reinforced the post-Nuremberg narrative that the United States fights wars reluctantly, in service of higher purposes—defending democracy, preventing genocide, securing peace. And it aligned naturally with the language of the Geneva Conventions, which frames IHL as regulating defensive, necessary uses of force rather than legitimizing conquest.
As of 2026, there does not seem to be any other country in the world that still uses, or has reactivated use of, the term “Secretary of War.”
In this post-1945 world, official names for military operations were chosen with care to signal moral purpose: "Enduring Freedom," "Unified Protector," "Inherent Resolve." However messy the underlying politics, the language consistently gestured toward ideals.
Hegseth's performative belligerence represents a sharp departure from this tradition. He prefers the older, blunter title "secretary of war." He has pushed for pardons of U.S. service members accused or convicted of war crimes, presenting them as victims of excessive legalism and timid rules of engagement. He frames the current war in Iran not in terms of protection or justice, but of vengeance: "Their war on Americans has become our retribution," with the declared aim of "death and destruction from the sky all day long." And he has branded the campaign "Epic Fury"—foregrounding anger and punishment rather than defense or protection.
It is important to appreciate just how unusual this is by standards of 2026.
6. Hegseth’s Lack of Wisdom and the Erosion of the American Military Soul
The just war tradition, particularly in its practical elaborations, has always combined moral judgment, attention to long-term interest, and concrete choices designed to constrain war in light of the unavoidable fact that some shared future must eventually be built. In this domain, ethics and long-term interest do not merely coexist—they merge. It is in everyone's long-term interest that war be governed by rules. A lot of wisdom, hard-won from human failure over the millennia, has entered into the detailed formulations of contemporary humanitarian law and rules of engagement.
By way of conclusion, several points deserve emphasis.
First, from Lieber onward, American doctrine has consistently presented legal compliance as compatible with—and often essential to—military effectiveness. Discipline, legitimacy, and restraint help maintain unit cohesion, forestall strategic backlash, and preserve domestic and international support. By placing "lethality" in opposition to "legality," Hegseth recasts law as a pure drag on military performance—a framing that the American tradition has long and wisely rejected.
By placing "lethality" in opposition to "legality," Hegseth recasts law as a pure drag on military performance—a framing that the American tradition has long and wisely rejected.
Second, moral language gives soldiers a framework for understanding why they are asked to kill and to die. When the only articulated rationale is "retribution" or "Epic Fury," service members may carry a heavier moral burden afterward—particularly if public support erodes or turns to regret. This is precisely the kind of retrospective moral injury that many veterans of Iraq and Afghanistan have described.
Third, the Lieber Code insisted that war must never lose sight of humanity. Pardoning those accused by their own comrades of violating that humanity, and treating legal limits as "weakness," amounts to repudiating the very American document that helped inspire modern international humanitarian law.
Hegseth's language about a "Department of War," "Epic Fury," and "maximum lethality, not tepid legality" may feel bracingly honest to some—especially after the frustrations and moral ambiguities of Iraq and Afghanistan. But it risks erasing the very distinction between war and murder, between force and atrocity, that American lawyers and soldiers have spent generations trying to uphold.
In doing so, it puts at risk the American military soul—both as a moral force and as a reliable guarantor of national security.
The challenge, true to the spirit of the Lieber Code, is neither to pretend that American wars are pure humanitarian crusades nor to revel in war as righteous vengeance. It is to keep insisting that even in the harshest conflicts, the United States is bound—by its very own deepest traditions as much as by international law—to fight under the discipline of rules, reasons, and restraints.
That has been the Christian tradition, and therefore the Western tradition. It has very much been the American tradition. Note that my argument against Hegseth’s performative belligerence should be plausible even to those who believe the war against Iran has a just cause—for example, because Iran has long waged proxy war against America and Israel, funded terrorism, pursued nuclear weapons, and killed American soldiers through proxies. It should also be plausible to those who believe that the war was begun under legitimate authority.
In response to Marco Rubio’s appearance at the Munich Security Conference last month it was appropriate to talk of civilization panic: Rubio was reconnecting to the uglier parts of the Western tradition in response to such panic. But it was also fair to say that Rubio was squarely within the Western tradition. As opposed to that, Hegseth has placed himself far outside of the key themes of the Western tradition altogether. Not even close.
The tradition has seen figures like Hegseth before—and it is honest about the devastation such postures tend to leave in their wake.
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