War is hell. This aphorism is often ascribed to William Tecumseh Sherman, the Civil War general whose vision of total war was the most unflinchingly ruthless of any of the major leaders of that brutal conflict. Yet today the aphorism doesn’t quite fit. The modern American way of war is much neater, cleaner, and more precise. Law circumscribes war, and remote-control drones often carry it out. It tolerates fewer collateral casualties than anything seen in the bulk of American history. Modern American war is, or at least aspires to be, humane.

Yet in Humane: How the United States Abandoned Peace and Reinvented War, a characteristically provocative work of historical scholarship, Samuel Moyn forces readers to ask whether this shift in the character of war has a dark side. What if the new era of humane war makes it possible to have more wars? Longer wars? What if humane war is a prop for forever war?

Moyn, a professor of law and history at Yale, has spent the better part of the last decade picking fights with true believers in the international human rights project. Moyn argued that the modern human rights project was a much more recent invention than many believed and that it often functioned as a distraction from other worthy political projects for promoting equality. Now Moyn has shifted his sights to the law and politics of war. It is—like human rights—a field where the conventional narrative is one of onward and upward progress. The twentieth century saw brutal warfare, to be sure—but it was also marked by the first major international trial for war crimes (Nuremberg) and dramatic growth in the law of armed conflict and in the institutional apparatus for enforcing this law. Surely the growth of law—and the neater, cleaner wars it has helped produce—is a step forward. Or maybe it is all just a distraction.

Quest for Peace

Moyn starts his counternarrative with Leo Tolstoy. In War and Peace, Prince Andrei ponders the possibility that war’s horror will itself be a deterrent to war. Tolstoy himself experienced the horrors of war in his service in the Crimean War. The experience cast a long shadow. His literary output frequently critiqued the horror and foolishness of war. In his personal life, Tolstoy sought to live out in increasingly radical ways his commitment to Christian pacifism. In the process, Tolstoy contacted peace movement activists across Europe and in America.

The peace movement’s objective was to end war by political activism, which it pursued in tandem with antislavery activism in the United States and elsewhere. Tolstoy saw the projects as linked. Slavery and war alike devalued human life. To many at the time, eradicating either was unimaginable. But slavery was abolished in Tolstoy’s lifetime in multiple countries, and he played a role in Russian efforts that succeeded in abolishing serfdom in 1861. Could war be next?

The peace movement activists said yes, it could.

In the Absence of Peace, the Humane Imperative

A new movement got underway that differed somewhat from the peace movement. It was associated with the Red Cross, an organization founded by Henry Dunant in 1863. Like Tolstoy, Dunant had his own personally searing encounter with war’s horrors when he witnessed the Battle of Solferino (and perhaps more importantly, its grisly aftermath) in 1859. He played a catalytic role in starting a new project: codifying in formal treaties limits on the conduct of war. The immediate consequence was the Geneva Convention of 1864. It was modest in scope, seeking merely to provide for better care for the wounded. Its significance, though, was in seeking to utilize some of the same impulses that drove the peace movement without fundamentally critiquing war. Rather, it was content to regulate the conduct of war.

With this, Moyn has the key through lines in his story in place. One storyline is simply the brutality of war. That represents the status quo against which reformers worked. The main line of reform thinking was found in a peace movement willing to question the ethics of going to war in the first place. The alternative vision accepted war as an inevitable part of life and focused on how to humanize the conduct of war.

These two reform movements broadly track a longstanding division in the classical legal tradition between jus ad bellum, the law governing when one can go to war, and jus in bello, the law governing the conduct of war. Many historians of the medieval and early modern law of war have tended to dismiss the law governing the start of war as more ethics than real law. Moyn makes the case for paying more attention to the critics of the initiation of war.

It’s Hard to Make War Humane

Moyn focuses his attention on the limits of the campaign to humanize war. The new developments, he argues, did little to limit war. When Americans first decided to codify the laws of armed conflict during the American Civil War, Moyn argues that the project was more about empowering the military to take harsh measures than it was in restraining the war. When the Hague conventions were drawn up in 1899 and 1907, they were less concerned with “humane war” than with codifying military customs and providing “definitions of military necessity” (89). Wars against insurgents, guerilla forces, irregular troops, and colonial subjects left the domain of the rules of war altogether. Moyn points out that two centuries of conflict with Native Americans, wars fought almost completely without legal limits, shaped America’s tradition of war. European countries ruled colonial possessions with a heavy hand. America followed their example—and its own practice of “Indian Wars”—in managing its colonial holdings in the Philippines.

The peace activists were more ambitious than the humanitarians. In their willingness to critique war tout court, Moyn says, they were the “seers.” The more modest tinkerers with the rules for the conduct of armed conflict may have thought of themselves as more practical, but they in fact were at least equally ineffective and less insightful.

The unprecedented slaughter of the First World War demonstrated the limits of the humanization project—of jus in bello. The peace activists—the proponents of jus ad bellum—made important gains in the interwar period, with the Kellogg-Briand Pact strengthening a norm against aggressive war. The peace activists in this period appear, if anything, more practical, achieving more real-world results than the humanization advocates. Moyn still stops short of claiming that the Kellogg-Briand Pact was transformative, in contrast to two of his Yale colleagues who argue that the outlawry of aggressive war was one of the underrated turning points of twentieth-century history. In any case, the supposedly practical humanization side of the project disappeared in the background of World War II, as the Allies bombed whole cities into oblivion with nary a thought about ethical or legal limits.

Actually, there was some concern about ethics—but as Moyn points out, it was restricted to the European theater. The attitudes toward Japanese enemies were colored by racism that had long shaped the application of the laws of war. The tendency to ignore even the limited jus in bello persisted into the Korean War, a conflict whose sheer brutality on both sides has often been glossed over: civilians executed, civilian property destroyed, surrendering enemies shot down. More than that, Moyn notes that Korea also marked an arguable violation of the “new international rules of peace” (156) when General Douglas MacArthur decided to pursue the Communists across the 38th parallel into North Korea.

Vietnam and the New Movements for Peace and Humaneness

A new peace movement marked America’s involvement in the Vietnam conflict. Moyn notes that, for a change, war outside Europe prompted concern. Moyn also notes, more crucially for the book’s argument, that reports of atrocities partially fueled American outrage against the war. Rather than try to make the war more humane, the activists and protestors of the 1960s and ’70s focused on trying to end the war.

Meanwhile, elite lawyers connected with the International Committee of the Red Cross embarked on a renewed campaign to humanize the conduct of war. It was spearheaded by the Swiss lawyer Jean Pictet, who coined the term international humanitarian law (IHL) to describe the field; “humanitarians, militaries, and observers alike” now commonly use the expression (198). The end of the Vietnam War provided a window of opportunity for remaking the law in this area, and from 1974 to 1977 negotiators worked on what would become the “Additional Protocols” to the Geneva Conventions.

Moyn argues that the Additional Protocols were transformative to the field. Since the first Geneva Convention (1864), law had been “on the margins of war.” It made a few more inroads with the 1949 conventions, with new rules governing such issues as the treatment of civilians in occupied countries, the wounded, and prisoners of war. But the Additional Protocols covered dramatically broader ground—notably, establishing a clear prohibition on targeting civilians and prohibiting excessive collateral harm. According to Moyn, “Humanity would define the terms of violence rather than eking out minor exceptions on the margins of its reign” (200).

Although the United States did not ratify the Additional Protocols, they nonetheless shaped the conduct of American war both from the inside and outside. Inside, the military embraced a new role for military lawyers, who learned the Protocols as the default international standard (now regularly said to be customary international law binding even on countries that did not ratify). Meanwhile, human rights watchdog organizations monitor compliance with the newly expanded field of international humanitarian law.

The War on Terror as Humane War

Moyn describes the war on terror after September 11, 2001, as the ultimate inauguration of America’s new way of war. It was a broad, open-ended war. Moyn calls it “endless war.” This is legitimated by the fact that it can claim to be humane war.

The notorious torture memos and the abuse of prisoners at Abu Ghraib were the exceptions that proved the rule. Both were deviations from the norm of humanity in warfare. Both were subjected to intense criticism. But in neither case did the scandal lead to widespread agitation for the end of the war. Rather, the solution was more assurances that war would be conducted humanely.

Something had changed. Contrast this with an analogous situation in the Vietnam War. Whereas the Vietnam-era revelations about the massacre at Mai Lai led to efforts to end the war, Iraq-era revelations about Abu Ghraib led to efforts to make the American war effort more humane.

The Obama administration internalized this lesson like never before. It maintained an intense program of drone attacks—but insulated this form of warfare from critique by a formidable array of legal and “legal-ish” standards, policed by an army of lawyers. Donald Trump backed off a bit from the intensity of the Obama-era legalism—but only a bit. Moyn’s book was typeset well before Biden withdrew from Afghanistan, but it’s much too early to say that the Biden administration is going to deviate in any major way from the endless, ongoing war on terror, or from its humane safeguards (and legitimation) in law. As of the end of August, the New York Times reported that the latest iteration of drone strike guidelines was in the works.

Moyn has put his finger on a key shift in the way that Americans talk about and debate war. The historical story is compelling and thought-provoking, moving seamlessly in its coverage from activists to military operations to legal developments.


Despite the book’s undeniable brilliance, there are some curious holes in its story. Moyn does not prove that humane war makes war last longer; in a podcast about this book, he explicitly said that he is not trying to (and cannot) prove causation. Standards of historical proof for large-scale social change are endlessly debated. Historical changes are the product of countless factors that came before—and historians are often wary of making strong causal claims. (Did high taxes cause the American Revolution? What about fear of corruption on the part of the British ministry? Or objections to Parliamentary control? How does one disentangle these interrelated issues to make a causal claim?) Put that aside. Even on the book’s own terms, Humane raises lots of questions as to whether it is looking in the right place to understand some of the transitions that it identifies.

First, consider the relative priority of various factors in Moyn’s story. For example, there was a contrast between the way the American public processed news of atrocities in Vietnam and Iraq. In one, the public pushed to end the war; in the other, the public demanded an end to inhumane conduct. Sure, the shifting place of law in war was a part of the transition. But meanwhile, Moyn mentions—briefly—that there was a shift from a conscription-based military to a volunteer military, and that this is also part of the story of endless war. He is surely right. In fact, this seems so intuitively correct as an explanation for the shift in attitudes that one wonders why Moyn focuses on the humanization of the laws of war, rather than on the self-interest of Americans concerned about conscription, as the central transition. And one could easily multiply still other factors as significant in explaining the different reactions—different perceptions of the harm at issue (torture of enemies is different on various metrics from killing children) or different casualty rates in the two conflicts, for example.  

That a change in attitudes about the humaneness possible in war was also part of the mix also seems correct, to be sure. That surely justifies its study.

This brings up a second question about the history told, an ambivalence over whether this story about elite thought can support broader conclusions about popular attitudes toward war. Moyn is an intellectual historian and a lawyer by training. Both strands show in the story that he tells best: of a major shift in the way that thought-leader elites in law, policy, military leadership, and humanitarian activism approached the possibilities of war. But at times, Moyn wants to reflect on how the public more broadly responds to war. Why was opposition to war, writ large, mobilized in response to Vietnam, or to World War I for that matter? Why are people not similarly exercised about war in general amidst more recent debates over the war on terror? It’s not clear that the shift in the humanization of war is sufficient, or even necessary, to explain shifts in public attitudes.

One could imagine the story of humanizing war told as a subpart of a larger narrative about shifting attitudes toward pain and suffering in general. It brings to mind an analogy to the history of human rights—a field where Moyn has been, for the last decade, a leading scholar. Stories about the intellectual history of rights as a subject have been coupled with stories about public attitudes, cultural histories of other-consciousness, of emotion and empathy and their relationship to ethics and politics. Quite plausibly, the story of humane war needs to be told with attention to these same dynamics.

Meanwhile, as for the elites that Moyn chronicles in more depth, the story Moyn tells is open to the charge—already made at length by other reviewers—that he focuses too much on the laws of war’s recentness. Both jus in bello and jus ad bellum have a long history, stretching back to the medieval period.

None of these omissions in Moyn’s story necessarily undermines his conclusion. But they do indicate that the argument is, despite the sweeping narrative, rather narrow in its sources. It explains somewhat less than it provokes.

Political History in Search of an Agenda

In conversation with critics of his book in the weeks since its release, Moyn commented that he sees history as political and moral. This should come as no surprise to anyone who has followed Moyn’s writings. He in fact confesses to being a “moral and melodramatic writer.” But when it comes to the normative and political agendas underlying this book, Humane is less than direct. Readers have already interpreted the book in quite different ways: as a call for making war more brutal, as an ambivalent meditation on whether war can be abolished, as a more-or-less misguided exercise in “wonkfare” (trying to make a difference by addressing an issue that only matters to policy wonks). The wonkfare charge is probably the best-taken. But even it fails to capture quite where the book ultimately lands.

What, then, is the political takeaway? If the book is a critique of humane war, what is the alternative?

Should one oppose humanizing war on the theory that more horrible conflicts will lead to more pushback against war in general? Moyn does not actually suggest that we should want less humane wars—just that we should recognize that humaneness, as an end in itself, could dull the moral senses in other areas.

Should we want a broad peace movement for our time? At various times, Moyn gestures toward this as desirable. But he never exactly says what form this could take, or what its standard of success would look like. The history Moyn chronicles does not exactly make a war-eradicating peace movement seem realistic—at least not for the start of the twenty-first century.

A point that comes up obliquely at a few points in the book bears emphasizing more strongly: the idea that nations could eradicate war was at its height in the late nineteenth century, during the heyday of European empire and civilizational hubris. It was then easier to believe that the handful of powers in the world could eradicate wars amongst themselves. It was easier to imagine that war could be eradicated when all the relevant players—all of those that sophisticated internationalist lawyers were thinking of, anyway—shared a concept of Western civilization, of a progressive development of society, even of a Christian social framework (desiccated as it may have been). Diversity could be ignored because diverse peoples were relegated to subjecthood at the peripheries of empire. The imagined world peace was limited to peace among a relatively small number of relatively homogenous national elites. It’s hard indeed to imagine the abolition of war as anything other than an idealistic dream for anyone—certainly not if one has a realistic estimate of human sinfulness.

Is the book, then, nothing more than a cynic’s campaign to find a dark side to everything? That’s not fair to Moyn either.

At the very least, Moyn wants Americans to debate the merits of war—and the moral criteria upon which it should be judged. Humane is a warning: Don’t be lulled into a false sense of complacency as war becomes less gory. In the final pages of the book, Moyn asserts (citing Tolstoy) that the “deepest evil in politics in general and war in particular is moral subjugation” (324). Moyn thinks that even if we could avoid killing entirely—even if a war were fought entirely amongst robots—it could be morally wrong. Limiting killing, pain, or violence should not obscure the fact that behind any conflict is a choice, and that choice should be open to debate. Moyn might describe this as a political choice. It is also a moral choice. For Moyn, antisubjugation is the moral criteria that appears clearly only at the very end.

Humane exudes cynicism toward the complacently optimistic assumptions of humanitarians, that what is humane is therefore good. In denying that this is an unalloyed good, Humane seeks to point readers—subtly, to be sure—toward a more open, robust, and morally forthright debate about any given war or military engagement. Humane does little to address the moral criteria to employ; Moyn only shows his cards at the very end. But if Humane is to nudge Americans toward greater moral reflection and application of moral criteria to foreign policy—war most especially—this would be a welcome result. Readers of Providence, who are interested in the application of Christian principles to foreign policy, should find this a welcome invitation. Humane is effectively a call to work harder at the political, moral, and religious task of wisely analyzing the decision to go to war.