The American Rules of War

America’s conflicts since 9/11 have thrust the question of the conduct of war into the public consciousness in a way not seen since Vietnam. What is the difference between a soldier and an unlawful combatant? Is the latter protected by such international agreements as the Geneva Conventions? Can an unlawful combatant claim the protections of the US Constitution, especially the writ of habeas corpus? What limits may be placed on the interrogation of detainees?

Most Americans seem to believe that such issues are new and that the laws of war were much once simpler than they are today. But as John Fabian Witt shows in his splendid and elegantly written new book, Lincoln’s Code: The Laws of War in American History, “controversies over the laws of war and novel questions of great difficulty are as old as the republic.”

The laws of war in American history, Witt argues, have sought to balance two principles: humanitarianism on the one hand and justice on the other. As such, the laws of war not only have served to constrain the actions of the combatants during a conflict but also to vindicate the purpose for which the war was fought in the first place.

The centerpiece of Witt’s book is an account of the events surrounding the drafting of General Orders No. 100 by the émigré German jurist, Francis Lieber, a code for the conduct of war for use by Union armies in the War of the Rebellion. While drafted by Lieber, Witt makes the case that the code is more properly seen as Lincoln’s, since it arose out of the crucible of slavery. “For it was Lincoln’s Emancipation Proclamation that required [the code’s]  production and sent it out to the world.”

But Witt’s story begins much earlier with a little known incident involving a young George Washington, who in 1754 was accused of violating the laws and usages of war by executing the commander of a French force during the opening clash of the Seven Years War, called by the British in North America the French and Indian War. In his initial report, Washington claimed that the French commander was killed in the initial exchange of fire before the French surrendered.

However, two month later, when Washington surrendered Fort Necessity to a superior French force, he hastily signed an article of capitulation that acknowledged the French commander’s death as a “treacherous killing” in violation of the customs and usages of eighteenth century warfare. Washington later denied any intent to sign such an acknowledgement, blaming his interpreter for the error, but the damage was done. “For years afterward, Washington’s reputation would be tarred by the affair of Jumonville Glen and its aftermath at Fort Necessity.” Witt contends that this event would shape Washington’s actions as a soldier “in a formal display of honor to ensure that war’s chaos would never again damage his reputation.”

Witt then traces the evolution of the laws of war in America from the Revolution to the end of the nineteenth century. The American approach was shaped by the founding generation’s battle against a British Empire that viewed them as traitors and by conflict with Indians who fought by different rules. The American understanding of the laws of war was also influenced by the existence of slavery. While European writers such as Emmerich de Vattel and Jean-Jacques Burlamaqui argued that it was permissible to seize the private property of the enemy during wartime, Americans demurred. They argued that it was impermissible for an enemy to seize private property, especially slaves, contending that to do so was to incite servile insurrection. This position would have consequences during the Civil War when Lincoln issued his Emancipation Proclamation.

During the early years of the Republic, American statesmen grappled in particular with the issue of the rights of neutral states in wartime as the United States was buffeted between Great Britain and France, the two great powers of the early nineteenth century. They also had to deal with the fact that the 18th century norms of warfare were ill equipped to govern the Indian wars in which the United States was engaged. During the Mexican War, American military officers established military commissions to address the problem of guerrillas. All of these issues set the stage for Abraham Lincoln and Francis Lieber’s attempt to codify the laws of war.

Lincoln’s first problem was to clarify the character of the war for the Union. Lincoln denied that the Confederacy was in any sense a separate nation-state. He consistently maintained that the Southern states had never left the Union; instead the attempted secession constituted a domestic rebellion.

Thus up until the bombardment of Fort Sumter, argues Witt, Lincoln had treated secessionists as criminals rather than enemies. Had he pursued this approach, the result would have been war with England and France, and more importantly, the likelihood of a downward spiral of destructive violence as the Union fought for its preservation and the Confederacy sought to achieve independence as a slave-holding republic. But eventually, Lincoln pursued a hybrid approach that, while incoherent as a matter of international law, nonetheless smoothed relations with neutral European powers on the one hand and made the war to preserve the Union less violent than it could have been.

A key accomplishment of Lincoln’s approach was to reunite the components of the laws of war that had been split by post-Enlightenment writers. Witt argues that the medieval Christian “just war” tradition subordinated jus in bello (just conduct of the war) to jus ad bellum (just cause). “When opposing armies were each equally convinced of their own righteousness, the medieval theory of just wars risked plunging warfare into uncontrollable cycles of destruction.” The Thirty Years War seemed to confirm this result.

In the wake of the Peace of Westphalia, European wars tended to be limited dynastic affairs in which the conduct of the war could be separated from the cause of the war. Theorists such as Vattel introduced a way of separating means and ends, “a way of preventing pursuit of war’s purpose from obliterating regulation of its means.” The Wars of the French Revolution and the Napoleonic Wars, of course, returned war to its unlimited character but the laws of war lagged behind.

Witt argues that the code that Lieber drafted and that Lincoln approved reunited jus in bello and jus ad bellum. Thus while it achieved a humanitarian goal by constraining the combatants, it also sought to achieve justice by vindicating the goals of the war. As Witt observes, the laws of war provided a framework for ethical decision making that shaped Lincoln’s internal deliberations during the summer and fall of 1862, culminating in the Emancipation Proclamation.

According to Witt, “the end of slavery was the quintessential event for the laws of war in American history.” As noted earlier, Americans had traditionally argued against the power to seize private property, especially slaves. In addition, emancipation seemed to pose a substantial humanitarian risk: the possibility of a race war such as had occurred in Haiti during the 1790s.

But Lincoln moved ahead with emancipation anyway, convinced that his cause—saving the Union and ending slavery—was just. So while Lieber’s codification of the laws of war served as a “humanitarian shield,” constraining the actions of the combatants, it also served as a “sword of justice,” a way of advancing emancipation, which not only freed slaves but also ultimately resulted in the arming of 200,000 black soldiers—what Frederick Douglass called the “sable arm”—who would help to end slavery once and for all. The code ratified a distinctly American understanding of the laws of war, not only providing constraints on the means available to armies in the field but also serving as a “tool for vindicating the destiny of the nation.”

Of course, Lieber’s code addressed other issues as well: the blockade of Southern ports, the treatment of Confederate privateers, the creation of military commissions, the treatment of prisoners, especially black soldiers who were captured by Confederate troops. The code also applied to Reconstruction.

In light of today’s wars involving fighters who hide among the civilian population, article 82 of General Orders No. 100 dealing with the treatment of guerrillas is of interest. Such individuals or bands of individuals, “if captured, are not entitled to the privileges of prisoners of war, but shall be treated summarily as highway robbers or pirates.”

Lincoln’s Code makes it clear that Lieber was no pacifist. Indeed, Lieber’s codification of the laws of war was heavily influenced by Carl von Clausewitz, the prophet of modern war. Thus article 29 reads, “the more vigorously wars are pursued, the better it is for humanity. Sharp wars are brief.”

Article 30 articulates the Clausewitzian principle that war is not its own end, “but the means to obtain the great ends of state, or to consist in defense against wrong. “No conventional restriction of the modes adopted to injure the enemy is any longer admitted; but the law of war imposes many limitations and restriction on principles of justice, faith, and honor.” “To save the country,” Lieber wrote, “is paramount to all other considerations.”

Witt observes that the circumstances surrounding the drafting and issuing of General Orders No. 100 differed from the usual pattern of making rules of war, which have usually come after conflict. “Humanitarians usually fight the last war when they make rules for the next one.” But when Lieber drafted his code, the United States was in the midst of a war the character of which was to change with the Emancipation Proclamation, which struck at not only the war-making potential of the Confederacy but also the heart of the Southern social system. As Lincoln wrote to Cuthbert Bullitt in July of 1862, the time had come to stop waging war “with elder-stalk squirts, charged with rose water.”

Witt completes his story by examining the era of war with the Plains Indians and the Philippine Insurrection, where in many instances, Americans failed to live up to the principles behind the code. He points out that Lieber’s code soon crossed the Atlantic, becoming the foundation of codes of conduct for European armies as well as the Hague and Geneva Conventions and related law.

The laws of war, like all law, were not handed down to Moses on the mountain, but evolved as circumstances have changed. The laws of war are a species of prudence, Aristotle’s practical wisdom, that cannot be studied without regard to context or the needs and interests of the concerned parties. But Witt argues that the laws of war have not merely served American self-interest. “If the law of war were nothing but the condensed interests of particular constituencies at particular moments, it could not do the work that it does—work in which American leaders since the founding have invested heavily.”

Lincoln’s Code is a fascinating look at an important topic. As the world’s only military superpower, the United States has a major interest in the laws of war. Witt has done justice to this complex issue by examining the American history of the laws of war and their meaning for the morality of military force in the twenty-first century.

Additional links: Liberty Law Talk discussion with John Fabian Witt, author of Lincoln’s Code.