IN JUNE 1859, a struggling Swiss banker named Henri Dunant caught up to the French army at the small town of Solferino in northern Italy. Dunant was seeking the French emperor, Napoleon III, in hopes of gaining the emperor’s consent to water rights critical to Dunant’s failing agricultural venture in French-controlled Algeria. Napoleon had marched from Paris with an army 120,000 strong to fight the Austrians on behalf of Italian unification, and Dunant had set off after him.
By chance, Dunant arrived at Solferino in the evening following a massive battle. Some 250,000 soldiers, French and Italian on one side, Austrian on the other, had fought in the heat of a blistering day. Now 30,000 wounded and 6,000 dead lay on the field. A late afternoon squall quickly turned the town’s roads into impassable mud, hindering efforts to reach the injured, let alone move them off the field. Those among the wounded who were able to evacuate themselves seemed to fill every available space in the already crowded town. Overwhelmed doctors performed battlefield amputations by the hundreds. The groans of thirsty and desperate men filled the air. Wounded men on all sides begged passersby to put them out of their misery.
Like a good Swiss businessman, Dunant tried to organize the situation. He mobilized teams of local women to bring food to the injured and to wash their wounds. He dispatched others to collect linen for bandages. He drafted boys as water carriers. He conscripted tourists, journalists, and businessmen into his efforts. He extended aid to the wounded regardless of nationality. Injured soldiers, he said, had no country. They were all brothers. Dunant’s efforts could hardly match the magnitude of the suffering on the field that evening, or the next day, or even the next day after that. But in a modest way, he had a made a difference.
Around Europe, men and women were having experiences startlingly like Dunant’s. In Great Britain, Florence Nightingale organized British hospital services in the Crimea and captured the attention of English newspaper readers with her indictment of the treatment of the sick and wounded. In Naples in 1861, a doctor named Ferdinando Palasciano delivered lectures proposing that wounded soldiers be treated as neutrals outside of combat. In Paris, a French pharmacist named Henri Arrault proposed a system of military ambulances that all armies would agree to exempt from attack. In the United States, New Yorkers including the designer of Central Park, Frederick Law Olmsted, and the prominent lawyer and diarist George Templeton Strong founded a Sanitary Commission to deliver aid to the wounded in the Civil War.
Back in his hometown of Geneva, his Algerian enterprise now in ruins, Dunant marshaled these disparate efforts into an organized project. He started by writing a book about what he had seen. He called it A Memory of Solferino. The book was a stunning exposéof war’s suffering. Behind the grand narrative of battle with its charges and countercharges, its heroic defenses and its sweeping assaults, Dunant revealed thousands of stories of extraordinary suffering: acts of brutality, smashed skulls, amputated limbs, and unendurable wounds. Suffering, Dunant forcefully insisted, was the real story of war. He distributed the book privately among friends in Geneva. His friends seemed to like it, so he printed more copies. Soon the book was being published in Leipzig, Paris, St. Petersburg, and Turin. Reform-minded men and women took up his work all across Europe. Dunant had touched a nerve. His powerful story did for the treatment of the wounded in Europe what Harriet Beecher Stowe’s Uncle Tom’s Cabin had done for slavery in the United States. But Dunant was more programmatic in his efforts than Stowe. His heartrending stories drew the reader ineluctably to a proposal at the book’s end: a plan that would offer humanitarian care to the wounded on the field. Dunant proposed the creation of a new international organization that would formalize on a massive and far more effective scale the ad hoc volunteer efforts he had patched together in the aftermath of battle in 1859.
With the help of wealthy Swiss colleagues, Dunant convened conferences of European states at Geneva in 1863 and 1864 to craft terms for a treaty that would formalize the ad hoc system of volunteers he had put in place at Solferino. The first Geneva Convention followed. Twelve European states—including Belgium, Denmark, France, the Netherlands, Prussia, and Switzerland—took up one of the Enlightenment’s great devices for limiting the destructive effects of war at sea and applied it to make new humanitarian progress in war on land. They agreed to treat ambulances and military hospitals not as enemies but as neutrals. The men and women employed in them, as well as inhabitants of the vicinity helping the wounded after a battle had finished, would be treated as neutrals, too. A distinctive arm badge—a red cross on a white ground—marked off its wearers as neutral humanitarian workers and thus exempt from the vicissitudes of combat.
DURING THE CIVIL WAR, Francis Lieber had lobbied his friends Henry Halleck and Charles Sumner to appoint him as the American delegate to the 1864 diplomatic conference in Geneva. “Am I not the man that ought to be sent?” he pleaded. But the pressing business of the Civil War, as well as the United States’ long tradition of avoiding entanglements in European diplomacy, prevented Lincoln and Secretary of State Seward from officially participating in the Geneva conference. A skeletal delegation of the U.S. Sanitary Commission attended, but only for the limited purpose of sharing information about humanitarian work in the American conflict.
What Lieber had grasped was that new proposals for the laws of war were emerging all around the Atlantic world. “Our No. 100,” Lieber told Halleck in 1864, had contributed its share to “the progress of our race,” and now the advancement of civilization was continuing onward. Countless factors seemed to press in the same direction. War correspondents like William Howard Russell, who covered both the Crimean War and the Civil War for The Times of London, brought the face of battle into the homes of a burgeoning (and increasingly literate) middle class. The founder of the New York Times, Henry Raymond, reported from the field at Solferino, where he encountered Dunant wearing his trademark white suit in the midst of the carnage. War photographers like Roger Fenton in the Crimea and Mathew Brady and Alexander Gardner in America did in a few iconic pictures of death what the newspapers did in thousands of words. Armies themselves were changing. Eighteenth-century mercenary armies led by aristocratic officer corps had given way to vast mobilizations of citizen soldiers, imbued with the nationalistic spirit of the age. Even the weapons those soldiers used were different in ways that summoned a new legal architecture for combat. Improved rifling technology—the grooved barrels in infantry muskets—rendered obsolete the compact fighting formations of Napoleonic warfare and undid the tight boundaries of the eighteenth-century battlefield. The same technology that mowed down George Pickett’s men at Gettysburg in 1863 also empowered irregulars ranging from Confederate guerrillas to the so-called Franc-tireurs of the war between France and Prussia in 1870–71. All these things—and more—prompted new initiatives in the laws of war.
Indeed, an entire generation of humanitarian reformers soon came to hope that the American code of 1863 and the Swiss convention of 1864 might be signs of a new epoch of moral progress, one that would not only ameliorate the horrors of war but one day even abolish it altogether. War had been a scourge of mankind since the beginnings of time, to be sure. But so had slavery. If the nineteenth century had managed to abolish the master’s lash, why not the soldier’s sword as well? In the United States, men such as the prominent Massachusetts pastor Richard Salter Storrs and Charles Loring Brace, the influential secretary of the New York Children’s Aid Society, wrote best-selling books and delivered public lectures citing Lincoln’s instructions for the Union armies as evidence of just such moral progress. The British jurist Sheldon Amos thought there was reason to believe that humanitarian reform would nurture “the very moral sentiment which, in time, will become the direct agency for the abolition of War itself.” Many of the men behind the Geneva Convention in 1864 aimed one day to end the wars that for the time being they sought to humanize. Dunant signaled as much in his Memory of Solferino, where he echoed Sumner’s early pacifism. War, Dunant said, turned men into murderers. Others, like the Swiss Gustave Moynier, who took over leadership of the International Committee of the Red Cross when Dunant proved too abidingly eccentric, told his fellow members of the organization that in the long run the brotherly sentiment nurtured by the Geneva Convention would make war itself seem as atavistic and barbaric as the acts of cruelty that the laws of war already prohibited. “La civilisation de la guerre—the humanizing of war—could end only in its abolition,” Moynier declared.
Reformers’ ambitions, however, ran ahead of the facts on the ground. Getting the states of late nineteenth-century Europe to agree to the Geneva Convention had proved relatively simple. Its terms dealt only with wounded men whose usefulness to any of the armies of Europe had, for all intents and purposes, come to an end. Indeed, it was not peacemakers who turned Dunant’s Geneva principles of 1864 into a new body of international law, but rather some of the most uncompromising statesmen of the day. The militarists of Prussia (an army with a state, rather than a state with an army, the French revolutionary figure Mirabeau had quipped) took up the Geneva project of humanitarian aid to the wounded with more energy and enthusiasm than virtually any country in Europe, save perhaps Switzerland itself. When Prussia fought and decisively defeated Austria in 1866, it already had in place 120 different networks of volunteers to do the work of caring for the wounded under the Geneva rules. In the United States, which had not been formally represented in Geneva in 1864, the Senate finally ratified the convention only in 1882, when it acted at the behest of Secretary of State James “Jingo Jim” Blaine, whose central diplomatic legacy was to set the United States on a path toward more military interventions in Latin America.
Outside the relatively narrow issue of wounded soldiers, however, the leaders of powerful states were highly suspicious of any attempt to extend Dunant’s humanitarian constraints into combat itself. Prussian military leaders objected vehemently to the barely concealed pacifist leanings of the humanitarian reformers. Field Marshal Helmuth von Moltke, the long-serving chief of staff of the Prussian army, spoke for many in Germany and elsewhere when he derided “perpetual peace” as “a dream,” and “not even a beautiful dream” at that. War, he insisted, fostered “the noblest virtues of mankind”—courage, self-sacrifice, and fidelity to duty. And although civilization had brought with it a general “softening of manners,” von Moltke warned that limiting the excesses of war was best left to the discipline of modern armies, not to the humanitarian efforts of lawyers and reformers. “The greatest kindness in war,” von Moltke told the prominent European international lawyer Johann Caspar Bluntschli, “is to bring it to a speedy conclusion.” Indeed, by the end of the century German officers worried that “it was impossible both to conduct a war successfully and observe the laws of war.” Military necessity, they insisted, took “absolute precedence over any considerations for the law and customs of war.”
Reaching consensus on rules of conduct was made even harder by the dense thicket of European rivalries. Proposals from the Russians immediately came under suspicion in Britain and Germany, where statesmen searched for ulterior motives. Suggestions from powerful states such as Prussia seemed to threaten small states such as Belgium, whose efforts in turn seemed designed to make hostile occupation as onerous as possible for strong occupiers and as gentle as possible for weaker occupied nations. Whenever the laws of war implicated the balance of power, diplomatic efforts came to a standstill. If international lawyers were to gain the consent of the states of Europe, they would need to accommodate themselves to the claims of powerful armies while finding a way to sidestep the rivalries of European politics.
THE AMERICAN GENERAL ORDERS of 1863 arrived on the European stage as a kind of deus ex machina in the emerging drama of the European laws of war, one that offered a way to break the logjam that had blocked negotiations over the laws of war.
The document was instantly influential. As soon as Lincoln issued it, Lieber had sent copies to lawyers and statesmen in Berlin, Heidelberg, and Paris. European jurists understood exactly how useful the American contribution could be. Indeed, they sometimes seemed to claim American roots for their law of war projects whenever possible. Bluntschli dedicated his influential work to “Professor Dr. Franz Lieber in New-York” and credited “Präsidenten Lincoln” and “Professor Lieber” (“mein lieber Freund!”) as his inspiration. He cited Lieber as inspiring the Institute of International Law, an important organization he founded with other international lawyers in Ghent in 1873. His Modern Laws of War of Civilized States (Das moderne Kriegsrecht der civilisirten Staten), which became the Germans’ text on the laws of war in the Prussian wars with Austria and France, was little more than a translation of Lieber’s “Old Hundred.” Bluntschli’s work was littered with references to the American Civil War code (the Amerikanische Kriegsartikel). Five years later, Bluntschli drew on Lieber’s Code to put into print Lieber’s new term in the laws of war: “war crime,” or Kriegsverbrechen in the German. Lieber had used the term, though not in print. The idea had been implicit in the American experience from the Mexican War forward. Under the aegis of Lieber and Bluntschli, the idea of the war crime would shape the culture of warfare for at least the next century and a half.
General Orders No. 100 inspired imitators all across Europe. Bluntschli’s work appeared in 1866 in Prussia. Military manuals on the laws of war followed in the Netherlands (1871), France (1877), Serbia (1879), Spain (1882), Portugal (1890), Great Britain (1894), and Italy (1896). Russia had a law of war manual in place by the time of the Russo-Turkish War of 1877–78. As the distinguished English jurist Henry Sumner Maine said, Lieber had set an example of “the formation of a practical Manual” that could be adapted to suit “the officers of each nation.”
To harmonize the proliferating manuals on the international rules of warfare, members of the Russian foreign ministry developed Lieber’s code into a proposal for a pan-European conference in 1874. When an ambitious midlevel civil servant in the Russian Ministry of Foreign Affairs named Fedor Fedorovich Martens first suggested the conference, he prepared a private draft for the Russian war minister that carefully cross-listed the articles of Lieber’s code alongside the parallel provisions of his own proposed text. When the convention delegates assembled in Brussels in 1874, Martens introduced the initial draft convention as an amended version of Lieber’s work in the Civil War.
Lieber’s handiwork in 1862–63 was indeed apparent in the Russian proposal. Following Lieber’s response to the 1862 prisoner parole controversies, Martens described the parole of prisoners as something permissible only with the consent of both the captor state and the captive’s own government. Lieber had responded to the guerrilla problem and the threat of slave insurrection by providing that noncombatants who rose up in a territory already occupied by the enemy were not legitimate combatants and were liable to be treated as criminals; Martens followed suit. And like the code of 1863, the Martens draft left vast discretion to the doctrine of “military necessity.” If necessity so demanded, even the execution of prisoners was permissible in Martens’s initial draft, just as it had been under the terms of Lieber’s code. Necessity, on Martens’s account as in Lieber’s, allowed the “seizure and destruction of everything that is necessary to the enemy in order to carry on the war,” as well as everything that “hinders the success of warlike operations.”As humanitarian critics noted at the time, even the gentlest provisions of texts like the Lieber code of 1863 and the Brussels Declaration of 1874 were shadowed by potentially eviscerating exceptions for the imperatives of military necessity.
Crucially, the American example offered an ingenious solution to the most difficult and contested issue in European law of war debates. The questions about guerrilla fighters that had arisen in Mexico in the 1840s and that Lieber had addressed in Missouri in 1862 turned out to be very much like the fast-emerging problem of irregular soldiers in European warfare. Were irregular combatants eligible for the privileges of prisoners of war? In 1871, when French farmers had fired on Prussian occupiers, the Prussians had required that any combatant be commissioned by a competent authority or otherwise be treated as a criminal. The Prussians had executed Franc-tireurs by the score. But the Prussian policy proved hotly controversial. And in the aftermath of the Franco-Prussian conflict, insiders thought that the hardest question to resolve in the laws of war would be “to whom does the right of combatant belong, in the case when a war is one of peoples, when the population, or a portion of it, has taken up arms?” The strong armies of Germany proposed a hard-and-fast rule favoring occupiers. After the eighth day of a conflict, they said, the privileges of lawful soldiers ought to be extended only to those wearing uniforms and acting “in direct subordination to a supreme commander-in-chief”; all other fighters would be simple criminals from that day forward. Smaller states, however, refused to go along, no doubt imagining with trepidation the risk of future German occupation. Belgium, which had good reason for concern, argued in favor of the opposite rule. Populations rising in self-defense, the Belgians contended, ought to be given all the privileges of soldiers indefinitely.
Lieber’s approach to the problem in 1862 cut through the knot of strong states and weak states. Martens, in particular, drew self-consciously on the functional strategy Lieber had crafted for defining soldiers and distinguishing them from criminal guerrillas. At Brussels in 1874, Martens adopted Lieber’s functional redefinition of legitimate combatants, minimizing the significance of formal commissions and official uniforms, and emphasizing instead characteristics such as command control, distinctive insignia or marks, the open carrying of arms, and the observance of the laws and customs of war. By the end of the century, these four functional characteristics of soldiers had solidified into a widely accepted definition of the soldier, and indeed they have lasted as suchinto the twenty-first century.
The American instructions of 1863 also helped men like Bluntschli and Martens distinguish themselves and the laws of war they meant to promote from the efforts of the secret pacifists at Geneva. Lieber’s personal views were far closer to those of the German von Moltke than they were to those of the Swiss Dunant. Bluntschli said of Lieber that he remained “fully aware that, in time of war . . . the harshest measures and most reckless exactions cannot be denied; and that tender-hearted sentimentality is here all the more out of place, because the greater the energy employed in carrying on the war, the sooner will it be brought to an end, and the normal condition of peace restored.” The code Lieber had drafted was made up of rules that could appeal to the strong states of Europe and even to the most unsentimental of Europe’s military men. Lincoln, after all, had adopted the code not to make peace but to make war. He had done so at just the moment when his nation’s wartime fortunes seemed at their nadir. And Lincoln had won his war.
The American code had made the laws of war safe for the powerful states of late nineteenth-century Europe, just as it had for the Indian wars in the American West. In doing so, it touched off a battle over the meaning of international law in wartime. Would the laws of war be merely a tool for powerful armies? Or would accepting the idea of constraints slowly shape the conduct of strong states? Could a law of war that deferred to von Moltke also create meaningful moral limits on war’s destructiveness?
IN A CONTEST for the soul of the law of war, Alfred Thayer Mahan would have played the Devil. An exceedingly tall man, with a bald pate, Mephistophelean beard, and baleful glare, Mahan was born on the campus of the Military Academy at West Point in 1840, the oldest child of Dennis Hart Mahan, who was the academy’s dominant figure for fifty years. From 1821 to 1871, the elder Mahan had adapted the axioms of French military strategy to instruct cadets in the conditions of American combat. He raised his children in a military spirit of rigorous and unquestioning adherence to rules. He gave his son the middle name Thayer in honor of Sylvanus Thayer, the superintendent of the Military Academy who had reorganized the school according to the professional standards of the French military model and defended its independence against Andrew Jackson’s political meddling. As a boy, the younger Mahan grew up at West Point in a household that combined what Mahan’s biographer calls “strict military obedience” with “a stern, literalist and fundamentalist form of Episcopalianism.” His father’s life was so bound up in the rigid order of the Military Academy that when Dennis Hart Mahan was at last forced out of the academy in 1871 at the age of sixty-nine, he stepped off the rear of a Hudson River steamboat into the vessel’s churning wheels and killed himself.
It is too strong to describe Mahan’s life as a rejection of his rulebound upbringing, though some biographers have been tempted to do so. His great act of defiance—signing up for the Naval Academy in Annapolis against his West Point father’s wishes—looked more like thinly disguised emulation than rebellion. Yet one way or another, Mahan came to be known as a student not of rules but of power. Where his father had mastered the axioms of nineteenth-century tactics, Mahan became his generation’s great prophet of power at a moment in history when an increasingly strong United States had begun to wield global authority.
In 1890, while serving as an instructor at the new Naval War College in Rhode Island, Mahan became a celebrity in the Atlantic world when he published a book entitled The Influence of Sea Power Upon History. Two years later, he published a sequel: The Influence of Sea Power Upon the French Revolution and Empire. Mahan’s thesis was that the exercise of power—and in particular the use of navies—propelled modern history. Over the next twenty years, as the world’s strongest states engaged in an arms race on the seas, Mahan became the voice of a new age of naval power. His work was translated widely and read around the world. Books and articles poured from his pen right up until his death in 1914. So great was Mahan’s influence that more than three decades later, Henry Stimson, who served as U.S. secretary of war in World War II, would remember the Navy Department of Mahan’s era as existing in “a dim religious world in which Neptune was God, Mahan his prophet, and the United States Navy the only true Church.”
In virtually everything that he wrote, Mahan presented world history as the story of armed struggle. “Step by step,” he wrote, “man has ascended by means of the sword.” Mahan disavowed jingoism and wars of conquest. But he believed that just causes required powerful nations to use force to vindicate the right. “Power,” he contended, was “a faculty of national life” given to particular peoples by God, and God expected those peoples to exercise it righteously.
Law was a thin reed in Mahan’s stormy battles for justice and civilization. Laws were mankind’s feeble attempt to codify universal moral imperatives. As a guide to moral action, he observed, they were often badly misleading. Some laws were simply unjust. In the pre–Civil War republic, Mahan liked to say, men of principle had defied fugitive slave laws. And rightly so. Nations, Mahan argued, had an even greater obligation to do justice in the face of misguided laws, for nations had a far greater capacity than individuals to use force in the name of righteousness, regardless of what the law said. Mahan conceded that it was dangerous to encourage lawbreaking. But he could come to no other conclusion than that it was a nation’s inescapable duty to evaluate its moral obligationswithout undue deference to the dictates of the law.
Mahan’s low regard for law made him a striking choice when, on the eve of a new century, Secretary of State John Hay selected Mahan as a delegate to a conference in The Hague convened by Czar Nicholas II to hammer out a new international law of war and peace. And yet for Hay, the choice was a natural one. Thirty-five years before, Hay had served as President Lincoln’s private secretary. Now Hay chose a man very close to the ideas of war and law that Francis Lieber had infused into the code of 1863 and that Lincoln had developed over the course of his presidency. Lieber, too, had rebelled at elaborate legal schemes that sought to substitute themselves for first principles of justice. Now Mahan, by force of his ideas and his overpowering personality, became the dominant member of the American delegation at the conference that would turn the code Lincoln issued in 1863 into the founding document of the twentieth century’s laws of war.
IN AUGUST 1898, the Russian foreign minister Count Muraviev surprised diplomats to the Romanov court by handing out a proposal for a conference on European disarmament and peace. (Ethan Allen Hitchcock, nephew and namesake of Civil War generalEthan Allen Hitchcock, accepted the message for the United States.) News of the czar’s initiative quickly electrified resurgent peace movements around the world. In the United States, in particular, where pacifists were still recovering from the blow of the Civil War, the inheritors of the antebellum peace societies reacted with a special jolt of enthusiasm. Here at last, in a conference convening the great states of the world, might be a forum that could live up to the grandeur of their ambitions.
The enthusiasm of hopeful pacifists, however, was matched by the cynicism of diplomats and military men. Mahan saw the czar’s call for the Hague conference as a defensive reaction to the new fact of U.S. power after the brief Spanish-American War of 1898. The American ambassador in St. Petersburg wrote to Secretary of State Hay warning that the United States should discount “the humanitarian aspect” of the Russian proposal. In “the ordinary Russian mind,” he said, “the semi-oriental influences and traditions of the people have bred in them a slight regard for the value of human life.” Others speculated that the czar’s ministers were desperate to find a way to slow a European arms race with which the Russian treasury could no longer keep up. No wonder Andrew D. White, the longtime American diplomat chosen as the leader of the American delegation, expressed a “hopeless skepticism” about the conference’s prospects.
In May 1899, delegations from twenty-six countries gathered in The Hague. They represented twenty European states, as well as four from Asia (China, Japan, Persia, and Siam), plus two from the Americas (Mexico and the United States). The delegates met at the House in the Wood, a seventeenth-century summer palace built just outside of town for the wife of the Dutch Stadholder, Prince Frederick Henry of Orange. It was a stately brick mansion with crisp white window frames and exquisite gardens. Over the door to the conference room hung an allegorical painting (by a protégé of the Flemish painter Rubens) of the Peace of Westphalia, the system of seventeenth-century treaties that had brought an end to the brutal Thirty Years’ War and initiated the modern system of European states.
But not even a felicitous site could overcome the obstacles standing in the way of agreements on most of the conference’s agenda items. When the delegates turned to the business at hand, it quickly became clear that arms agreements of the kind the czar’s ministers seemed to desire would be impossible to attain. Any agreement to freeze in place an existing technology, or to reduce the growth of arms budgets, would create winners and losers. No such agreement could gain the unanimous consent of the delegations. Secretary Hay, for one, had instructed the U.S. delegation flatly that they were not to enter into any arms limitations discussions because the U.S. level of armament was so low compared to European powers.
Proposals for the peaceful arbitration of national disputes fared only slightly better. Arbitration was a favorite of the American peace movement, which saw the United States as international arbitration’s great champion. Twice in the nineteenth century—once after the War of 1812 and then again after the Civil War—the United States had successfully arbitrated disputes over British conduct in wartime. But arbitration, too, faced high hurdles at the conference. In particular, Germany opposed the idea of obligatory arbitration (Mahan did too), and the German position forced the Hague Peace Conference to adopt a watered-down system of purely voluntary arbitration. The English jurist Thomas Erskine Holland dismissed it as amounting “to really nothing.”
Russian statesmen thought it imperative for the czar’s reputation that something concrete come out of the conference. And so, facing inability to get agreements on armaments or mandatory arbitration, the delegates turned to the laws of war. Over the course of the summer of 1899, the delegations took the Geneva Convention’s rules for wounded soldiers on land and adapted them for naval warfare. They debated limits on the means and methods of combat. And most important of all, they forged a general revision of the laws and customs of war. The Russian minister F. F. Martens, who had initiated the Brussels talks a quarter century before and who now headed the Hague committee charged with updating the laws of war, credited Lincoln and Lieber with creating a blueprint for the committee’s work. Martens adopted Lieber’s functional evaluation of prisoner of war status. But the Hague committee took the American example and built on it substantially. Even the American delegation described the work of the committee as a distinct advance on the Civil War code of 1863. Where Lincoln’s instructions had permitted the execution of prisoners when a commander found himself in “great straits,” the Hague Convention prohibited prisoner execution altogether and required humane treatment under all circumstances. (For one thing, the signatory states of Europe and North America now all had the administrative capacity to hold and maintain prisoners without being strategically disadvantaged.) There was a difference in the spirit of the two documents as well, though it was not clear whether or how this translated into differences in the law. In the 1863 rules, Lieber had set out a terrifying list of the kinds of violence that war admitted and had admonished that sharp wars were shorter and thus more humane. He had written that, above all, saving the country was the paramount consideration. The Hague Conference’s law of war convention, on the other hand, cautioned against destruction, observing in a clause usually attributed to Martens that even in the absence of a particular rule or prohibition, “populations and belligerents remain under the protection and empire of the principles of international law” in wartime.
Nonetheless, the delegates proved to be sharply divided on critical questions, including the core question for humanitarian law. Were limits on war’s destructiveness really humanitarian at all? The conveners insisted that they were. The Russian president of a Second Hague Conference in 1907 would warn that while he had “heard the opinion expressed that it was an absolutely mistaken idea to seek to diminish the horrors of war,” it seemed to him “an absolutely specious opinion.” Yet that was precisely the opinion Mahan held. Indeed, the theorist of naval power held views closer to those of von Moltke and Lieber—and even Clausewitz—than to those of the humanitarian reformers. Mahan saw the world in bleak terms; Andrew White liked to say of Mahan that “when he speaks, the millennium fades.” But Mahan was not alone in his skepticism of humanitarian reform. Secretary Hay’s instructions to the American delegation approached legal limits for war with much the same caution. With respect to new forms of explosives, as well as to aerial projectiles launched from hot air balloons and new and more destructive technologies of naval warfare, Hay instructed the American delegates to the Hague Conference that it was “doubtful if wars are to be diminished by rendering them less destructive.” To the contrary, Hay warned, the “plain lesson of history” was that “periods of peace have been longer protracted as the cost and destructiveness of war have increased.” Moreover, as Hay saw it, limitations on new technologies of destruction were especially dangerous for the United States, since “the inventive genius” of entrepreneurial Americans was one of the nation’s great strategic advantages.
Mahan ensured that the U.S. representatives would vindicate Hay’s skeptical view. Andrew White, who headed the U.S. delegation, was no lightweight. He had been president of Cornell University and minister to Germany and Russia. He was the sitting ambassador to Germany when the conference began. But he was no match for the forcible Mahan.
The imposing Navy man also completely dominated Captain William R. Crozier, the American military delegate. Crozier was better known as an inventor of artillery devices than as a diplomat or strategist. He could claim credit for the Buffington-Crozier disappearing gun carriage, but he turned out to be out of his depth at the conference. Once Mahan got to him, however, Crozier served as a perfectly adequate mouthpiece for Mahan’s views. In committees on which he represented the United States, Crozier first voted in favor of prohibitions on projectiles from hot air balloons and on so-called dumdum bullets that tumbled or expanded inside their target. But after Crozier consulted with Mahan, he changed his views on both questions. New technologies, Mahan admonished, might well improve navigation and make it possible for balloons to deliver decisive firepower to the battlefield without undue risk to noncombatants. In the long run, aerial warfare might thereby become the favored humanitarian way of war, reducing war’s death toll and shortening its duration. In the right circumstances, the dumdum bullet might similarly turn out to be more humane than any alternative. British major general Sir John Ardagh, for example, contended that in combat in Africa or India,dumdum bullets could stop an onrushing savage when ordinary bullets would not. Crozier offered a substitute provision that would have prohibited the use of bullets inflicting “wounds of useless cruelty.” When the conference rejected his substitute, Crozier and the British delegate cast the only two votes against the dumdum bullet ban. No other country joined them.21
Mahan himself took the lead role for the United States in discussing a proposed prohibition on the use of projectiles designed to spread asphyxiating gases, and here too he took a position against the weight of the conference. As White later recounted, Mahan believed that a ban on poison gas “would prove to be rather harmful than helpful to the cause of peace.” Mahan announced that it was illogical and inhumane to be “tender about asphyxiating men with gas, when all were prepared to admit that it was allowable to blow the bottom out of an ironclad at midnight,” thus causing 400 or 500 men to drown. Mahan’s logic was the same with gas as it had been with balloons. Who was to say that under certain circumstances, gas might not be more humane than the gruesome destructive force of traditional military ordinance and explosive charges? It was the same logic, moreover, that Francis Lieber had brought to the laws of war and that had initially inclined him to oppose a ban on the use of poisons when he gave his public lectures on the laws of war at Columbia Law School in the winter of 1861–62. Though White initially opposed Mahan on the asphyxiating gas rule, he soon gave way to his colleague. At the end of the conference, the United States would vote against the prohibition on dumdum bullets, against the ban on asphyxiating gases, and would insist on a sunset provision limiting the prohibition on projectiles from hot air balloons to five years.
Even then, Mahan was not done. Secretary Hay had instructed White to push for the immunity of private property at sea. Few ideas were nearer to the heart of the American law of war tradition. Ben Franklin had promoted the idea in the 1770s and 1780s. So had John Quincy Adams in the 1820s. William Marcy and Franklin Pierce had advocated the immunity of private property as an alternative to the privateering prohibition of the Declaration of Paris in 1856. But privately Mahan was violently opposed to any attempt to exempt private property from seizure in wartime. Indeed, he even resisted the old American position that free ships made free goods, the rule under which neutral ships’ cargoes were to be immune from seizure at sea. Stopping commerce on the high seas had been a critical factor in Britain’s defeat of Napoleon, and the anglophilic Mahan was loath to let that power slip out of the hands of the American and British navies now. The Russian conveners kept the issue off the agenda in 1899; but when delegations returned to The Hague in 1907 for a follow-up conference, Mahan persuaded President Theodore Roosevelt, Secretary of State Elihu Root, and a new U.S. delegation to torpedo any movement to exempt private property, even though such an exemption was still officially part of the American program at the conference. Echoing Mahan, Secretary Root told the British foreign secretary Sir Edward Grey and the U.S. delegation that the threat of losing property in sharp wars at sea would incline the world toward peace. Indeed, the risk of losing their property would turn merchants around the world into a permanent lobby for peace. Grey agreed; “limited liability” wars, he said, were dangerous. The immunity of private property at sea would have to await another day.
FOR ALL THE Peace Conference’s limits, the law of war convention at The Hague was a considerable success. Mahan may have helped to reign in the conference’s most ambitious initiatives for controlling the means and methods of war. But relying in large part on American contributions from the Civil War onward, The Hague conference had produced a treaty for the law of war on which a large share of the world’s sovereign states could agree. The Hague Convention even endorsed the form of the 1863 pamphlet. It required its signatory states to issue instructions to their armed forces, instructions to be drawn up in the image of Lincoln’s instruction manual for the Union armies.
Yet there was a difficulty haunting the laws of war even at the moment of their apparent success. Would the conduct that had once seemed morally permissible for the world-historic ends of abolition also prove justified in wars of empire? The conceit of the Enlightenment’s customs and usages of warfare had been that the permissible means and methods of war could be understood independently of the justice of the cause in which they were deployed. The Civil War code had called that premise into question. But at the turn of the twentieth century, wars of empire sundered the connection between the new laws of war and the moral force of the antislavery effort that had precipitated their birth. Therein loomed a crisis for the law.