Reviewing Samuel Moyn, Humane: How the United States Abandoned Peace and Reinvented War (New York: Farrar, Straus and Giroux, September 2021), 416 pp.

Samuel Moyn’s new book is already an electric moment in the history of international law.

In a field sometimes prone to self-congratulation and ethical confusion, the force of Moyn’s moral vision is a shock to the senses and an antidote to complacency. Contemporary warfare, he argues, is characterized by a world-historically novel focus on minimizing the human toll of conflict. But war’s new emphasis on the humanity of its conduct, Moyn continues, has not been an unmixed good. To the contrary, Moyn contends that our ostensible ideals have smoothed the unjust exercise of power and paved the way to a dystopian future in which domination by force may evade the checking function of a legal order focused narrowly on collateral damage. If grim images of destruction don’t populate the political discourse of western democracies, Moyn cautions, powerful states are further empowered to use their militaries to dominate others with reckless and dangerous abandon. Here is an urgent idea of the foremost moral importance. Its argument merits consideration by lawyers, historians, and citizens of every country. Moyn’s searing book is about nothing less than the mechanisms by which the powerful of the planet control the weak.

But, dear reader, I should begin with words of confession.

I have been in conversation with Moyn about these ideas and this topic for well over a decade. He and I taught a seminar on the history of the laws of war at Columbia University in 2007 when we were both learning about the subject for the first time. Relying on our seminar discussions, I published my book Lincoln’s Code on the laws of war in American history in 2012 – a book that Moyn cites generously in his own and also critiques. And Moyn and I have resumed co-teaching at Yale, where we are friends, co-directors of the Law School’s Legal History Program, occasional fishing partners, and sometimes sparring partners in public discussions, though I’d like to think that Moyn’s famous energies in intellectual debate mean that he usually gets the better of me, regardless of the merits of the argument in question. I am an admirer and I suppose an insider critic. And from that position I have a few observations about Moyn’s new book. His warning about the present and future of warfare comes embedded in an opinionated tour of the history of law and war, with a pronounced emphasis on the United States, which is the principal target of his argument. I know something about this topic, having written on it not too long ago. I can’t tell if you should discount my views because I am too close, or if my reactions may be of value because I have followed the argument so closely.

Either way, here’s my take.

Moyn’s account presents a confounding mix of brilliant moral vision with maddening historical omissions and one-sidedness. He sees the world, it seems, with the same shock that he so powerfully conveys to his reader. His is the vision of the idealist meeting the grim and unjustifiable arrangements of the world in which human beings live and have lived. Moral force arises out of that posture. But the book’s moral urgency comes with an accompanying risk. The phenomenon of law facilitating and channeling the authority of powerful states is not new, not some upstart development with shallow roots susceptible to being plucked out in a burst of energetic mobilization. No, law’s role as an enabler of domination on the world stage is at least as old as the system of international law and its component states, and undoubtedly much older still. If we don’t understand the problem’s true depth and the relationship between law and power, we will be poorly positioned to really grapple with it, at least in a fashion likely to do more than reproduce the underlying dynamics in new form. Let me see if I can explain.


Moyn persuasively shows that a certain kind of humanity is importantly new in war. The laws of armed conflict, he says, often didn’t even aim to limit damage against civilians, and in any event they rarely succeeded in such effort. He is onto something in this claim. The presence of lawyers peering over the shoulder of officers, applying the law of proportionality to military targeting decisions, is a stunning new development of the past several decades. It is even more astonishingly new when force is applied in parts of the world that standard international law excluded from its protections until recently because of race prejudice and white supremacy. International law scholars like Kenneth Anderson, Gabriella Blum, Amos Guiora, Jack Goldsmith, Oona Hathaway, David Kennedy, Naz Modirzadeh, and many others have documented parts of the phenomenon. Moyn adds an urgent voice to the growing literature.

But the general effort to minimize civilian damage is a much older effort that has run hand-in-gauntlet with the interests of strong military states. Seventeenth-century armies developed internal codes of regulation designed to focus their soldiers use of force on enemy combatants. All too often, soldiers raped and pillaged in unarmed civilian populations in the countryside, often for private gain. Soldiers did this in part because it was considerably less dangerous than attacking heavily armed enemy soldiers. But such private conduct was often less useful, if not counterproductive, for a prince or a commander seeking to apply force against his enemy. The first modern codes of war protected civilians in order to make armies more effective tools of states, not less, and to make war (as my colleague James Whitman’s recent book showed) more useful as a dispute resolution mechanism. The production of new norms against injury to those not armed yet close to the battlefield was a side effect of the European political projects.

The co-evolution of military power and legal restraints on death and destruction also implicates a subject Moyn unduly discounts. Technological determinants like the drone and the precision-guided missile make much of our new twenty-first-century moment possible. This is not the first time technology has helped generate new law purporting to offer a more humane way of war. In the middle of the nineteenth century, the advent of steam-powered navies led the powerful states of Europe to enter into a treaty purporting to humanize conflict by banning the use of private vessels to terrorize enemy shipping on the high seas. The prohibition on so-called “privateering” in the 1856 Treaty of Paris ruled out a tactic relied upon by weaker powers like the United States, which had bitterly protested the treaty before clumsily reversing its position when the Civil War found the North with greater regular naval power than the South. A few years later, the invention of easily used rifled infantry weapons sent shock waves through the law of war, producing the modern law governing guerrilla combatants in the Franco-Prussian War and the western theater of the American Civil War.

As Moyn knows, distinguished critics have attacked the humanization of war for at least two hundred and fifty years. In the mid-eighteenth century, Frederick the Great proposed that “short and lively” wars were more humane than the polite wars imagined by the jurists. Nineteenth-century theorists of war like Karl von Clausewitz in Prussia and Francis Lieber, a Clausewitz student in America, made similar observations, as did Prince Andrei in Tolstoy’s War and Peace, whose moral vision Moyn treats as inspiration. If all these characters could mobilize arguments against the law’s humanization of war, then surely the law was aiming to humanize war, and sometimes even succeeding in doing so, at certain times and in certain places and in certain ways. Millions of prisoners of war who lived to tell their stories testify to the point. Countless more millions of soldiers whose truce flags permitted surrenders that succeeded in ending a conflict serve to illustrate the same idea. Rules for prisoners, truce flags, and surrenders are legal norms and practices designed to limit war’s destructive effects – and also to make war more effective as a tool of powerful states. We know this already.

The advocates of short and sharp wars were not the only critics of humanity in war. Others rejected humanity altogether in favor of justice as the central governing ideal. Abolitionists in the Civil War called for what Lincoln finally called “the hard hand of war” because they rejected American slavemasters’ contention that the civilized laws of armed conflict barred interference with slavery on southern plantations. For nearly a century, beginning with Virginia whites in 1775, Americans had insisted that the laws of war protected the private property of slaveowners and prohibited the stirring up of slave insurrection and the humanitarian nightmares that were said to be certain to follow. Lincoln fired his commanding general in the summer of 1862 for defending these allegedly civilized claims.


Qualifications about his treatment of the history of humanity in war notwithstanding, Moyn is on the strongest ground in his historical claim when he focuses on the novelty of targeting lawyers and newly exacting humanitarian standards for collateral damage. New developments are indeed afoot here.

When, however, Moyn says, as he occasionally does, that law’s involvement in war is more generally a radical novelty, his excess of enthusiasm for the thesis leads him beyond his narrower and sounder argument and into historical error. Law is not obviously more “central to the warrior’s code” today than in earlier conflicts. It’s just different. Moyn writes that before the 1970s “one could say with only a bit of exaggeration that there were no laws of war, humane or not” (p. 200). Only righteous historical blinders and a kind of historical hubris could lead one to such an error. The laws of war have arisen out of armed conflicts, and in turn shaped, enabled, and channeled them, for millennia. Consider that in the modern world, for example, war itself cannot really exist, at least not since the seventeenth century, without special dispensation from the law. Killing another human being is almost universally subject to the criminal laws of the place in which the killing happens – unless that act occurs during the state of war, in which case it isn’t. One of the first thing the laws of war accomplish is to immunize the soldier from prosecution for homicide. The distinction between war and crime is entirely an artifact of the law, and it has been part of the warrior’s code for centuries, even if observed in the breach. The distinction between war and crime has been contested nearly since its invention in the seventeenth century, to be sure, but that is of no use to Moyn, since the law of humanity is today contested, too. The point is that social action in war has long been deeply moralized and subject to legal regulation, it’s just that the law and the morals have been different. War has been and is saturated with norms and meanings, and the laws of war have embodied war’s moral dimensions, even if the moral issues at stake have been unlike those that preoccupy humanitarian lawyers today.

No example looms larger for Moyn’s argument than strategic aerial bombardment in the Second World War. Decades of failure to produce rules for airplane-delivered munitions led to “mass death of civilians, first as Japanese cities were razed by fire, and then as two nuclear bombs were dropped with no thought about the rules of international law” (p. 131). The case is even stronger, since as Moyn notes, the allies firebombed European cities like Dresden, too. And urban saturation bombing of the kind that took place in 1945 at Dresden and Tokyo offers the starkest counterpoint to the precision munitions and law of proportionality of today. Surely here is evidence of a sea change.

But what kind of a change is less clear. Moyn sometimes champions the few who spoke up on behalf of law against indiscriminate area bombing (pp. 133-34). And sometimes he reminds us that the law in the 1930s and 40s was woefully inadequate in its effort to regulate indiscriminate killing from the air. The Hague regulations prohibited bombardment of undefended places. But jurists disagreed about what kinds of defenses counted. The failure of the law here, however, should hardly surprise. The laws of armed conflict arise out of the agreements and practices of states. It can be no better than the states it regulates, though sometimes advocacy campaigns and cooperative equilibria can help states express their ideals. But the fact that the law did not proscribe aerial bombardment is no more evidence against the law’s significance than the fact that law permits dangerously high speeds is evidence against the significance of the law of highways. The pervasive violation of traffic rules does not mean there are no stop signs or that stop signs are irrelevant. The same is true with more urgent examples. The grim fact that settler colonial societies stole land from indigenous peoples is not evidence against the significance of the law of theft. The dreadful and persistent fact of police killings with little legal consequence does not mean there is no law of murder.

The law of war in the past may not be familiar to us today, but it was a law of war nonetheless by every definition of the term. Consider the Civil War moment I know best. Moyn makes no mention of the Emancipation Proclamation, an action Lincoln defended on the ground that it was licensed by the law of war. Moyn should have included Emancipation, since it might have supported his assertion that until recently the laws of war licensed violence toward civilian life. One senses that the case is omitted because its complexity doesn’t fit the narrative. Emancipation is an example where the use of force against a society’s self-designated civilian infrastructure was not evil but righteous. Although not as glaring an omission ,where, too, in his account is the United States’ admirable defense of Black prisoners of war against the official Confederate policy of executing them and their white officers as criminals? Here was an episode in which insistence on doing justice – standing up for Black soldiers – was strategically useful and culminated in a humanitarian disaster. Recruitment of Black soldiers was crucial to the late stages of the U.S. war effort. At the same time, insistence that the South treat them as soldiers rather than criminals led to the breakdown of prisoner exchanges and to the deaths of tens of thousands of white prisoners in horrific POW camps at places like Andersonville.

Other missing pieces mar Moyn’s account. Where is the sometimes successful and always stunning insistence on decent standards for prisoners of war? Moyn’s focus on the law as humanity leads him to understate law’s legitimation effects in past moments of combat, for example between Native Americans and the U.S. in the American West after the Civil War, and in the Philippines a few decades later. He omits to mention the convictions of American soldiers for war crimes in the Philippines, and strangely says that there is no evidence of any legal interpretation calling for constraints on American force (p. 112). The congressional hearings on which Moyn and his sources rely for evidence of U.S. abuses in the counterinsurgency efforts were products of the controversy Moyn denies existed. Legal proceedings did not put a stop to horrors. Those who were court martialed received light sentences. But the longstanding dynamic of enablement, constraint, and legitimation was firmly in place.

I hope it is clear that my point here is not to defend the moral structure of the law of war. The point is instead that law will inevitably be put to uses no better than the people exercising power in and around it. Before the Civil War, for nearly a century, American slavemasters and the U.S. government officials who worked for them insisted that the humanity of international law protected their property in people. George Washington began his career with the black mark after involvement in a massacre in the woods of Ohio that French critics called a gross violation of the standards of civilization. Andrew Jackson fueled the nation’s ugly fury against Native Americans by citing their departures from the European norms of warfare. American soldiers in the Philippines used torture in interrogations on a widespread basis, notwithstanding that their own army’s rules of for warfare prohibited the practice. It is no wonder that a young pacifist and future senator from Massachusetts named Charles Sumner condemned the law of war in the middle of the nineteenth century as “rules of wrong,” or that the great Mexican critic of international law Pancho Villa derided those rules as absurd seventy years later. When the laws of war have sought to assert right over might they have been a dismal failure more often than not.


The real history of the laws of war in the modern world has been a story of rationalizing and channeling the military power of states by connecting that power to a set of moral ideas about the use of force. This story is simultaneously a confession of weakness and an extraordinary accomplishment. Many like Sumner and Pancho Villa have mocked the effort to even try. Irrational power is a terrifying thing, and containing it, even at the margins, is no small feat.

Moyn’s book illuminates one way in which the process of milling power into ideals, and ideals into power, is taking place once again. It warns us that the rise of humanizing standards is not a new and unalloyed moral triumph, but a new iteration of the close developmental relationship between the force of powerful states, on the one hand, and the law that emerges in dialogue with that force, on the other. The availability of stunningly precise modern military technologies (technologies that we produced, to be sure) has yielded “humanity” as a component of the most recent legal regime to serve (partially) the interests of power.

Of course, if it were not so, if humanization standards did not align to some extent with the interests of powerful states, they would not be the law. Our legal order rests on the consent of those states, and so it could hardly be otherwise. The best the law can do is reflect our best selves, though surely it often mirrors our worst. Law does not come to us as if from The Good Place. It will not rescue us. It is us. It should hardly be surprising to find it no better than we are.

The truth is that Moyn’s book is not really about the law and its history, except more than by a glancing blow. His is a book with more explosive munitions and a higher priority target, but it lacks precision-guided coding. The book is not satisfied to confine its attack to the field of legal history (of the international variety or otherwise), but aims instead to disrupt the supply chains sustaining the blinkered moral gaze of an entire worldview. Until recently, state military power routinely included law-abiding force of jaw-droppingly brutal proportions. Now lawyers routinely insist on proportional targeting that minimizes civilian harm that was once routine. Moyn’s powerful claim is that we should not think the latter regime has abandoned the older legal project of enabling state military power. And he warns against the dystopian future of high-tech weaponry in which a handful of powerful states are able to dominate the planet and police its conduct in what he calls a “chilling” future of “war beyond killing” (p. 9).

The argument only goes so far. As you read this, the nuclear powers of the world have missile systems primed to do unspeakable inhumanity. To the abiding frustration of many humanitarian lawyers, the laws of war, at least according to the International Court of Justice, do not even pretend to call such strategic terror unlawful when the survival of the state is at stake. And surveys of Americans indicate that public opinion strongly favors the infliction of vast civilian damage and death among an enemy over deaths among American combatants. Our wars of humanizing standards perch atop a world poised to destroy all of humanity in mere minutes. Perhaps Frederick the Great was right. Reciprocal deterrence is the vindication of his thesis that the prospect of “short and lively” war may be humanity’s best defense.

I don’t think Moyn really disagrees that law has accompanied war since time immemorial. He says otherwise from time to time. But if pressed to be more precise and less provocative, he might concede that what is new is the particulars of the law’s content, not its salience, and not its relationship to power. As Moyn well knows, his own critical account channels Immanuel Kant’s eighteenth-century complaint. Kant called the lawyers and humanitarians of his own time the “sorry comforters” of power. Moyn echoes Leo Tolstoy, too, who serves in this book as a far-sighted prophet. Kant and Tolstoy are good company, and Moyn follows them by making his real target not humanity per se, which he applauds, all things being equal, but instead unjust domination by force. The power of Moyn’s critique rests not on the humanization of warfare, which critics uncharitably turn against him, but on the uses to which humanity has been and may be put in the future. The United States’ grim military bungling in Iraq and Afghanistan and elsewhere makes his argument as morally urgent as its partial and selective as a matter of history.

One senses that Moyn finds the compromise acceptable, and perhaps even morally required. The world, Humane suggests, is too terrible a place to be preoccupied by such niceties as historical fidelity or humanitarian lawyering. But I don’t think so. If the law limiting civilian damage is, among other things, continuous with a long history of powerful states establishing and exploiting the laws of war to advance their ends, then the right responses to the world in which we live will be very different than the ones to which Moyn’s book points. Humanitarian law is a desperate tightrope walk between horror and the awesome power of strong states. If he described it as such, Moyn would be less subject to the cheap critique that he wants to see more brutal conflicts. But he would also have to abandon his astonishment that the advocates of humanity have compromised with the world in trying to make it better.


Photo credit: The First Hague Conference in 1899: A meeting in the Orange Hall of Huis ten Bosch palace – collections of the Imperial War Museums