In his new book Humane, professor of journalism and history Samuel Moyn (Yale Univ.) addresses pacifists' quandary whether they should strive to abolish war altogether or aim for more modest (and more achievable) goal of making it more humane. He argues that the goal of the antiwar movements to curtail its excesses through ever more restrictive International Humanitarian Law (IHL) has legitimized continual humane war: hence, "endless war has become part of the way Americans live, on par with their Evites and online wedding registries." In short, the legal taming of war "has changed the face of one of the oldest practices in history" (4–5). Moyn believes Pres. Barack Obama perfected "humane war. "Alongside his reliance on no-footprint drones as a new mode of cleaner and more humane killing, Obama simultaneously turned to the light-footprint U.S. Special Forces" (268–69). While Moyn considers the humanization of war to be real, he also fears that the "brutal wars of the American past could return" or that "the elemental aim of endless war" may result in "the potentially nonviolent control of other peoples" (323–24).

Humane has two parts: the first, titled "Brutality," covers the period from the Crimean War (1853–56) to the Korean War (1950–53). Part II, "Humanity," covers the period from the Vietnam War (1955–75) to the War on Terror (2001–present). Moyn begins by explaining how war became more and more brutal from the mid–19th century to the mid–20th. This coincided with the ever greater influence of the international peace movement. In Part II, Moyn also argues that war was mitigated by increasing legal restrictions on how military force might be used without dictating when it could be used; this created the present-day "forever war."

Part I is more compelling than the second part, on the concept of humane war. Early on, Moyn criticizes the father of IHL, Franz Lieber (1800–1872), for limiting the applicability of his Code to regular warfare between states. Apparently, Lieber did not consider the Code applicable during the American Indian Wars (105–6). "The Lieber Code offered license rather than limits in counterinsurgency" (111), especially in colonial wars. Moyn argues that the rules established in the Hague Conventions could not restrain warfare during the First World War and hence "dealt a serious blow to the hope that someday humane war might come" as "not only were the laws of war violated without a second thought, but also the worst acts of war, the ones that met with the most moral outrage, were not illegal" (116). This eventually led to the vicious strategic bombing during the World War II. Moyn laments that in 1945 "as the Inferno [of the nuclear bombings] raged, never was the law of war deemed relevant, nor was any lawyer asked whether it was" (135). The Nuremberg Trials failed to turn the initiation of war into a particularly grave war crime. Instead of making war a crime, only certain behaviors in war were criminalized.

The second part of Moyn's book develops the idea of the legal transformation of the practice of warfare, which Moyn believes began in the Vietnam era. The Vietnam chapter discusses how IHL influenced American conduct during the war and how grave violations like the My Lai massacre helped end the conflict by bolstering the public's perception that the war was in itself unjust. Moyn suggests that the many legal curbs imposed on US forces even contributed to some of the excesses, being "not adequately designed for the realities of counterinsurgency" (167). During the Vietnam War, there was initially too little awareness among military leaders and lawyers that war crimes must be investigated and punished—a circumstance that changed only after they were widely reported in the media.

Post-Vietnam initiatives included an all-volunteer force (1971) that facilitated the "self-humanization of armed force" (209), and the strengthened role of Judge Advocate General's Corps lawyers, who have assumed a more central role in decisions to exert force. Unfortunately, while the use of force has since been much more constrained, it also seemed to encourage more interventionism: "more than 80 percent of all U.S. military interventions abroad since 1946 came after 1989" (226). "The drift into militarism" and the idea of using war to stop atrocities began during Bill Clinton's presidency, which justified US interventions in Somalia, Bosnia, and Serbia despite their questionable legality under international law.

The last two chapters review the War on Terror under presidents George W. Bush, Barack Obama, and Donald Trump. These chapters develop the concept of "humane war." The author handles the subject well, though his overarching argument that humane war now represents a final evolution of war is unpersuasive . Moyn explains how international lawyers, especially John Yoo, tried to make a legal case for war with Iraq and bend IHL to exclude terrorists from its protections by introducing the new category of "unlawful combatants." These were neither afforded the benefit of a trial nor treated as POWs under the Geneva Convention. Moyn argues that the 2003 "Iraq intervention had been illegal under applicable international law"; he underscores the failure of Americans to condemn the illegality of the Iraq War while denouncing the torture and other abuses of the War on Terror (255).

The transgressions that occurred under President Bush spawned the extreme "lawyerliness" of the Obama administration. Early on in his book, Moyn credits Obama with perfecting humane warfare (8). The drone warfare and targeted killing that escalated during the Obama administration epitomize humane warfare for Moyn. He also points out that the argument for anticipatory self-defense in the Iraq War came to justify targeted attacks on individuals posing a threat to the United States sometime in the future (288–89). Ironically, the humanized (drone) war triggered demands by activists and Non-Governmental Organizations for "even more humane war" with the paradoxical consequence of ignoring "that illegal war would be increasingly endless and everywhere" (294).

Humane fails owing to its unconvincing stress on only those practices of warfare that involve the US military. Ignored are the covert and proxy warfare typical of the American War on Terror. The drone warfare in Afghanistan and Pakistan may perhaps be called humane due to the relatively low number of casualties there. But the proxy wars in Libya and Syria (and now Ukraine) have been funded with American money and weapons; the resulting hundreds of thousands of deaths are hard to call humane, especially in view of the humanitarian disaster that these proxy wars leave behind. Progress toward humane warfare is far more fragile than Samuel Moyn realizes. War remains as bloody as ever regardless of honorable efforts to make it less so.