SO DECISIVE WAS Webster’s success that when war finally did break out, it was not with Great Britain, but with the United States’ neighbor to the south.
On May 11, 1846, President James Polk asked the U.S. Congress to declare war. “Mexico,” he told the members of the House of Representatives and the Senate, “has passed the boundary of the United States, has invaded our territory, and shed American blood on American soil.” Under Webster’s famous Caroline formula, Polk had offered a clear self-defense basis for war. When Mexican forces under Colonel Anastasio Torrejón crossed over to the north bank of the Rio Grande to attack General Zachary Taylor’s U.S. Army of Occupation, Polk reasoned, they had passed into and attacked the United States. The trouble, however, was that many in Mexico (and some in the United States) saw it differently. They believed the border was not at the Rio Grande but at the Nueces River, 150 miles to the north. Mexican officials insisted that Mexican blood had been spilled on Mexican soil. The commander of the Mexican Army of the North called Taylor’s crossing of the Nueces “unjust, illegal, and anti-Christian.”
Historians in Mexico and the United States ever since have carried on an inconclusive debate over the location of the U.S.-Mexico border and the legality of the United States’ decision to go to war. What neither Polk nor his critics guessed—and what historians have usually overlooked—was that in a year’s time the United States would be embroiled in a different controversy about the laws of war. Once again, the issue would be the difference between war and crime. And this time the American military would merge the two to create a forerunner to the modern idea of the war crime.
AT FIRST, the Mexican War followed the European conventions for regulating combat. Mexico and the United States each committed to follow the customs and usages of civilized war. Taylor and his Mexican counterpart Pedro de Ampudia agreed that “the laws and customs of war among civilized nations” would be “carefully observed” by the armed forces of both nations. The two generals communicated through white truce flags sanctioned by the laws of war. They entered into formal capitulation agreements allowing surrenders with honor. They followed the usages of war in their treatment of prisoners. Taylor readily exchanged prisoners and routinely paroled captured Mexican soldiers, officers and enlisted men alike, despite nagging worries that some paroled Mexicans were violating their oaths by taking up arms after their release. Mexican commanders likewise viewed captured Americans “as prisoners of war, to be treated with all the consideration to which such unfortunates are entitled by the rules of civilized warfare.” Captive American officer Seth Thornton, for example, reported to Taylor that “kindness and attention” had been “lavished” upon him and his fellow prisoners. Within a short time, Thornton was back in the U.S. camp, exchanged along with all his men for the equivalent number of Mexican prisoners.
Taylor and his subordinates issued proclamations assuring the Mexican people that they, too, would be “protected in their rights, both civil and religious.” As Taylor put it in June 1846, “We come to make no war upon the people of Mexico.” When the war neared its end in January 1848, Secretary of War William Marcy boasted proudly to the Congress that the conflict had been conducted “within the rules of civilized warfare.”
But if Marcy thought the Mexican conflict had not altered the laws of war profoundly, he was deeply mistaken. As the war dragged on, Marcy and his generals had made a critical change in how the laws of war worked.
In the war’s second year, acute new problems began to develop for the American armies in Mexico. Most of the 73,000 volunteers who served in the Mexican War behaved honorably. But infamous companies such as the 1st Pennsylvania, made up of members of a Philadelphia gang known locally as the “Killers,” had been stealing and robbing even before they crossed the Nueces and the Rio Grande. Once in Mexico, volunteers continued to commit the same kinds of depredations and worse. In June 1846, Taylor worried that the volunteers arriving daily in Mexico were proving to be “a lawless set.” By 1847, he was condemning many of them as “G-d d——d” thieves and cowards. The volunteers, complained Lieutenant George Gordon Meade, acted like “Goths and Vandals”; using the conventional racial categories of the age, Meade wrote that they seemed more “like a body of hostile Indians than of civilized whites.” According to General-in-Chief Winfield Scott, the atrocities were enough “to make Heaven weep” and to cause every American “of Christian morals” to “blush for his country.”
Regular army officers were not the only observers shocked by the behavior of the raw recruits. A Louisville Journal correspondent remarked that Taylor’s march from the Rio Grande toward Monterey “was everywhere marked by deeds of wanton violence and cruelty.” At Marin, the same newspaper reporter observed “pillage, robbery, and devastation.” Volunteers such as Henry Clay, Jr., son of the powerful Kentucky politician, were shocked at the “inhumanities” committed by some of their peers. George W. Kendall, a prominent New Orleans resident, expressed the same view in a manner common among white Southerners when he wrote in disgust that an American garrison near Punta Agua “had committed offenses that negroes in a state of insurrection would hardly be guilty of.” The behavior of Zachary Taylor’s troops left a lasting mark on his reputation, though not enough of one to prevent his election as president in 1848.
Mexicans committed atrocities, too. Throughout much of the war, Mexican authorities had a weak grasp on law and order. The Mexican presidency changed hands six times in less than two years. In the power vacuum, highway robbers preyed on American stragglers and Mexican civilians alike. Even before the onset of formal hostilities, bandits murdered Zachary Taylor’s popular quartermaster Colonel Truman Cross when he wandered outside the U.S. camp. American observers wrote home of murderers run rampant. “The weapon used in most cases,” George Kendall reported, was “a slim but exceedingly sharp sword-cane.” “So expert are the cowardly miscreants in their murderous office,” he wrote, “that but one stab is necessary to take life.”
Most of the Mexican acts were not acts of war, strictly speaking. So far as anyone could tell, they were ordinarily committed by Mexican nationals, not Mexican soldiers. They were the acts of civilian criminals. In the second year of the war, however, that was about to change.
IN FEBRUARY 1847, Mexican authorities switched their tactics. For the better part of a year Mexican armies had fought and lost one pitched battle after another. Now, as Winfield Scott led 20,000 soldiers from Vera Cruz on the coast toward the capital city, Mexican commanders abandoned the set-piece battles in which they had been so badly overmatched and adopted the irregular tactics that had only recently come to be called “guerrilla war.”
The new Mexican strategy modeled itself on the Spanish resistance to Napoleon some forty years before when peasants on the Iberian Peninsula had taken up arms to harass and demoralize the French-backed occupiers. Some Mexican military men had favored such tactics from the start. But the acting president of Mexico, Pedro Maria Anaya, made the turn to guerrilla tactics official in April 1847 when he called “for the establishment of a light corps to function as part of the National Guard.” Anaya’s proclamation went out to any “citizen having sufficient means and influence” to raise a unit of at least fifty men. The call echoed through Mexico. Wherever there were high concentrations of U.S. soldiers—in Puebla, Mexico, Vera Cruz, and Tamaulipas—guerrilla companies formed in great numbers.
Guerrilla detachments soon launched attacks on American wagon trains, especially those carrying goods along the critical supply line between Vera Cruz on the coast and Winfield Scott’s army in the interior. Early in 1847, guerrillas led a stunning attack on a massive wagon train of 110 wagons and 300 pack mules on the road from Marin to Monterrey. Fifteen hundred guerrillas commanded by General José Urrea hid alongside the road until the wagons and their small escort were surrounded. Lieutenant William Barbour, the commander of the American force, had no choice but to surrender immediately. The guerrillas cut the canvas wagon covers into crude sacks and filled them with everything they could carry away. Having taken all they could, the guerrillas opened what an American medical officer later called “an indiscriminate slaughter” on the Mexican teamsters who drove the wagons for the U.S. Army. The Mexican command had issued a standing order that no quarter be granted to Mexican nationals working for the Americans. Many of them “were burned alive on their wagons.” The bodies later recovered had been “most savagely mutilated.”
Guerrillas often hid in the thick chaparral along the roads and picked off stragglers from the American lines. Men went missing from the camps, only to be found days later, dead in the heavy brush by the roadside. One victim was found with a lasso around his neck and tied to a prickly pear; he had been dragged 100 yards through the underbrush.
Guerrillas like a one-handed former highway robber named El Mocho (“The Maimed”) quickly became infamous for their brutal treatment of American stragglers. When a young U.S. drummer was captured by El Mocho’s men, for example, he was assaulted,“dreadfully wounded,” and left naked “by the roadside to perish alone.” Days later, El Mocho encountered the boy again and killed him outright, cutting the drummer’s throat “from ear to ear.” One American soldier wrote home in 1847 that the guerrillas “murder the soldiers who may, from fatigue, lag behind our army.” Sometimes “they even cut our men’s throat, heart and tongue out, hanging them on a limb of a tree right over their bodies.”
To some Mexicans, the guerrillas were heroes. In the eyes of U.S. forces, however, they were villains. As guerrilla attacks mounted, American volunteers resorted to the same brutal and often counterproductive reprisals that Napoleon’s forces had employed in Spain forty years earlier. When Mexican guerrillas killed a private in the Arkansas Volunteers, the victim’s comrades chased a large group of Mexican men and boys into a cave at the Rancho Agua Nueva near Saltillo in northern Mexico and killed between twenty and thirty of them while they huddled inside. A month later, the Texas Rangers—already notorious for their rough treatment of Mexican civilians—retaliated for an attack on a wagon train by massacring twenty-four Mexicans at Rancho Guadalupe near the town of Ramos. In the suburbs of Mexico City in September 1847, the Texans avenged the death of one of their own by killing seventeen Mexicans. And when the popular cavalry officer Samuel H. Walker was killed later in the fall in an engagement with guerrillas near Huamantla, a “wave of vengeance” washed across the countryside. One historian has described the ensuing retaliatory violence as a “rampage of looting, destruction, murder, and rape.” American soldiers on the ground described it the same way. “All around me,” reported one Indiana soldier, “was desolation and ruin.”
Guerrilla attacks and American reprisals touched off a downward spiral of violence. Attempts under Zachary Taylor’s command to allow local Mexican officials to deal with criminal acts by guerrillas neither deterred guerrilla activity nor successfully stopped unauthorized American reprisals. As one Mexican observer remembered after the war, “desolation and death” had been “reduced to a system” along the roads of Mexico. Homes were left in ashes. Ranches stood deserted. “The dead bodies of men and the carcasses of mules lay unburied along with broken and plundered wagons.”
WINFIELD SCOTT, who arrived in Mexico in February 1847 to lead the campaign to Mexico City, was as well positioned as any officer in the U.S. Army to deal with the problem of guerrilla war. Trained as a lawyer in Virginia, he had distinguished himself for more than thirty years as one of the leading professional officers of the age. In 1812, Scott had been captured by the British in a battle at Queenstown in Canada. (He almost certainly would have been executed by the British army’s Indian allies if a heroic British officer had not intervened.) While serving as a prisoner himself, he had represented the United States in prisoner of war controversies for much of the rest of the war. In the decade thereafter Scott studied military operations in Europe, compiled the Army’s newGeneral Regulations, and wrote what became the drill manual for infantry in the U.S. Army. By 1847, he was general-in-chief of the U.S. Army, the Army’s highest-ranking officer.
Scott was also among the most well read officers in the early U.S. Army, and like many of his fellow officers he made the Napoleonic Wars of Europe his principal study. As the Mexican War progressed, Scott began to pay particularly close attention to the military failures late in Napoleon’s career. He read about Napoleon’s disastrous invasion of Russia and his catastrophic retreat back to France. And he read about the campaign of the Spanish guerrillas on the Iberian Peninsula in 1808. From Sir William Napier’s three-volume History of the War in the Peninsula and from Baron de Jomini’s writings on the art of war, Scott learned that a population aroused to guerrilla warfare could undermine the efforts of even the most well trained army.
Drawing lessons from Napoleon’s mistakes, Scott developed an innovative strategy for dealing with the twin problems of guerrilla attacks and indiscriminate retaliation by American volunteers. The first problem he took on was one he had been working on for decades: the discipline of his own soldiers. Zachary Taylor had long complained that he could not identify the perpetrators responsible for civilian deaths, even when they were his own soldiers. But if Taylor had been able to do so (and there was little reason to think he had tried very hard), he faced a seemingly insuperable problem: U.S. military authorities in Mexico lacked the authority to punish most crimes committed by American soldiers against Mexican noncombatants. The Articles of War, which traced back to the Continental Congress and which had not been significantly revised since 1806, left the authority to punish such crimes in the state and territorial courts of the United States. It had never occurred to the Congresses of the early republic that a U.S. army might fight a war of occupation in foreign territory. And so, when Taylor asked Secretary of War William Marcy in the fall of 1846 what to do with an American soldier who had murdered a Mexican soldier after the end of combat at Monterey, Marcy instructed Taylor that military tribunals were probably incompetent “to take cognizance of such a case.” Absent more authority from the Congress, Marcy advised Taylor simply to release the prisoner “from confinement and send him away from the army.”
Taylor meekly complied, but Scott thought Marcy’s advice absurd. Being discharged was exactly what disgruntled volunteers wanted most. American commanders in Mexico would never be able to maintain discipline over their men without the authority to punish those who committed crimes against the enemy.
Before he left for Mexico, Scott pressed the Polk administration to propose legislation to Congress authorizing military tribunals in Mexico to try such offenses. But neither the Congress nor the president was willing to act. Members of Congress claimed that there was no need for legislation because the president already had the power to try such crimes based on his authority under the laws of war. If he had such power, however, Polk failed to exercise it. As Scott later wrote, the question of an inherent executive power to enact a federal criminal code was “too explosive for safe handling.” In Scott’s homespun metaphor, Polk and Marcy handled the subject as gingerly as “the terrier mumbles a hedgehog.”
Scott took matters into his own hands upon arriving in Mexico. By his own order he created a new martial law authority over crimes committed by U.S. soldiers on foreign soil. Scott’s General Orders No. 20, issued at Tampico on February 19, 1847, authorized tribunals that he called “military commissions” for a wide array of acts deemed atrocities. He listed assassination and murder, malicious stabbing or maiming and rape, malicious assault, battery, robbery, theft, the wanton desecration of churches, and the destruction of public or private property. Military commissions were empowered to try any such offense committed by or upon a member of the United States’ forces, including offenses committed by inhabitants of Mexico. Scott issued General Orders No. 20 anew at each major juncture in the campaign across central Mexico. He distributed the order widely in English and Spanish at Vera Cruz in April, at Puebla in June, and at Mexico City in September.
Scott’s military commissions tried some 303 Americans during the Mexican War. As a mechanism for disciplining his own soldiers, his martial law innovation was a great success, a crucial piece of the widely praised campaign he waged from the sea to Mexico City. Indeed, Scott’s martial law order quickly became part of an American national mythology of chivalry in the Mexican campaign. It helped Americans view with pride the efforts of their army to bring order to the mounting chaos in Mexico. As one writer put it, the war had been fought with “chivalric generosity” and an “enlightened moderation” that connected the American armies in Mexico to “the best days of Knighthood.” Shortly after the war ended, the best-selling author Emma Willard wrote proudly that the“Mexican capital was not conquered by the American republic, as Carthage and other cities were by the Roman.” Mexico City had not been destroyed. It had not “become the sport of petty tyrants and a lawless soldiery.” Even critics of the war came to think that “no war, in any age or country, was ever waged upon principles so humane, so civilized” or “so Christian” as the Mexican War. Scott’s closest aides were positively effusive. “It would be a blessing to humanity,” gushed Lieutenant Colonel Ethan Allen Hitchcock, “if General Scott’s martial law order in Mexico could be recognized as an integral portion of the international law of the world.”
DESPITE HITCHCOCK’S PRAISE, one feature of Scott’s military commissions was actually quite strange. It was one thing to punish American soldiers and Mexican civilians within U.S. lines. Such authority had long existed in the basic structure of European and American militaries. The much harder problem was to understand how Scott had the right to punish commissioned members of the Mexican army.
Scott initially declined to bring regular Mexican soldiers or commissioned guerrillas into his commissions. His 1846 proposal for the Congress and for Polk and Marcy proposed to punish “inhabitants of the hostile country” who committed murder or theft or any one of a number of other crimes. General Orders No. 20 at Tampico in February 1847 similarly established jurisdiction over “any inhabitant of Mexico.” By “inhabitant,” Scott almost certainly meant noncombatants, since the word had long been used in military law as a term of art that excluded soldiers. Two months later, Scott confirmed that he did not contemplate prosecuting enemy soldiers. In a proclamation to the people of Mexico, he announced that “injuries committed by individuals, or parties of Mexico, not belonging to the public forces,” would be “punished with rigor.” Those who did belong to the “public forces” of Mexico would not, or at least not by Scott’s military commissions.
As late as October 1847, Secretary of War Marcy treated commissioned Mexican guerrillas not as criminals, but as soldiers entitled to prisoner of war status. Marcy excoriated guerrilla tactics, to be sure. They were “hardly recognized as a legitimate mode of warfare,” he wrote to Scott, “and should be met with the utmost allowable severity.” Guerrillas and their supporters were therefore not to be paroled or exchanged. But Marcy stopped short of suggesting that commissioned Mexican guerrillas were subject to criminal prosecution. Even guerrillas, he insisted, “should be seized and held as prisoners of war,” not prosecuted as criminals.
Yet as the war ground on into its final months, American officials subtly but crucially altered the legal status of Mexican soldiers engaged in irregular war. Even as Marcy articulated the view that guerrillas were generally entitled to prisoner of war treatment, Taylor began to redescribe guerrilla attacks on his wagon trains as attacks by “robbers.” The new description did not reflect a change in the underlying conduct of the Mexicans. Nor did it arise out of a change in the status of the Mexicans engaging in the conduct. Commissioned Mexican guerrilla parties were still assaulting wagon trains and killing the Mexican nationals they found acting as teamsters for the U.S. armed forces. Nonetheless, Taylor had begun to shift from the idiom of war to the language of crime.
The change in treatment moved slowly through the U.S. forces in Mexico. In the north, Brevet Major General John E. Wool decreed that “guerrilla parties” were “highway robbers under another name” and would be “executed wherever found.” Further south, Major Walter Lane’s Texas Rangers captured a guerrilla in late 1847 and executed him two days later after a hasty field tribunal. To ensure that word of the American attitude toward guerrillas would be spread far and wide, Lane ordered the guerrilla shot so that“as many Mexicans” as possible could “witness the execution.” When Major General Joseph Lane (no relation to the Texas Ranger) led antiguerrilla forces on an engagement at Sequalteplan, he made plans to execute the enemy commander as a criminal.
At the same time, the U.S. Army began convening informal military tribunals styled as “councils of war” to prosecute Mexican military recruiters caught trying to lure away American soldiers. Mexican recruitment efforts posed a real problem. Some 6,825 American soldiers deserted during the course of the war, nearly 7 percent of the entire Army; several hundred of them formed the San Patricio Battalion, made up mostly of Irish and German Catholic immigrants who signed up to fight alongside their fellow Catholics in Mexico. The military commission scholar David Glazier has identified twenty-one accused recruiters tried by councils of war beginning in June 1847. Eleven were convicted, and the punishment was “almost always death.”
In December, Winfield Scott drew on the councils of war for Mexican recruiters to formalize the treatment of guerrillas as criminals. General Orders No. 372, issued from Mexico City, announced that “atrocious bands called ‘guerrilleros’ and ‘rancheros’” were violating “every rule of warfare observed by civilized nations.” Many guerrillas acted under the commission and instruction of the Mexican authorities. But Scott no longer made such a distinction. “Whether serving under Mexican commissions or not,” Scott ordered that such guerrillas were to be sent before a “council of war” for “summary trial” according to “the known laws of war.” Councils of war, in turn, were to punish “any flagrant violation of the laws of war” by death or lashes, so long as there was “satisfactory proof that such prisoner, at the time of capture, actually belonged to any part of a gang of known robbers or murderers, or had actually committed murder or robbery upon any American officer or soldier or follower of the American Army.”
Scott’s councils of war were summary indeed, for there is almost no information in the historical record about the councils of war that tried guerrillas. No written transcripts were taken, at least none that survive. No general orders were published. As a result, we cannot be sure how many guerrillas were tried by council of war. Even the most thorough military commission scholars have found not a single surviving record of a council of war trying a Mexican guerrilla. But it seems clear that field tribunals in Mexico did exactly this. Colonel William Winthrop, who was the leading late nineteenth-century American authority on military law and who served in the Judge Advocate General’s office during the Civil War, wrote in the 1880s that “guerrilla warfare” and “violation of the laws of war by guerrilleros” were among the “principal charges referred to and passed upon” by the councils of war in Mexico. Winthrop had not been in Mexico himself, but he was in a position to know what had taken place there. Moreover, Winthrop’s report is corroborated by anecdotal evidence. Major General Joseph Lane’s antiguerrilla detachment reported using precisely such a field tribunal to execute a guerrilla in late 1847. And at least one American officer was punished for executing a guerrilla“without the sanction of a council of war.”
SCOTT’S PROSECUTIONS OF Mexican guerrillas occasioned little fanfare at the time. But they marked a transformative moment in the laws of war. The U.S. military had never seen anything like it before. In the Revolution, Washington had tried Major John André as a spy. But spies were not criminals in the ordinary sense. They were loyal servants of their country whose clandestine (and often heroic) missions exposed them to a particularly severe sanction under the rules of the game called war. Though the spy might be forgiven for overlooking the distinction, spies were executed because doing so was simply (in Vattel’s words) the only means “of guarding against the mischief they may do to us.” That was why a spy who successfully made his way back to his own army’s lines could no longer be executed, even if he was subsequently captured.
Nor were Andrew Jackson’s executions of the British subjects Arbuthnot and Ambrister in Florida in 1818 comparable. Neither Arbuthnot nor Ambrister were members of the British armed forces; they were private agents working on their own account and thus not protected as prisoners of war. The closest thing the United States had ever seen to Scott’s guerrilla prosecutions were the messy and ultimately inconclusive accusations leveled by Thomas Jefferson against Lieutenant Colonel Henry Hamilton (“the hair-buyer general”) in 1779 for stirring up savage warfare on the early frontier and mistreating American prisoners. But even there, Jefferson had stopped short of formally treating Hamilton as a criminal. At Washington’s urging, Jefferson had eventually relented and released Hamilton on parole as a prisoner of war.
Few precedents for Scott’s councils existed in the history of modern European warfare. Centuries earlier, medieval chivalric courts had tried violations of the laws of arms by knights from around Europe. But the courts of chivalry had long since dwindled into insignificance. By the time of the wars of the French Revolution and Napeoleon’s campaigns, controversial criminal punishments took place not between admitted enemy countries but in cases where one side denied that the other was entitled to the privileges of a sovereign state in wartime. When Napoleon arrested and executed the exiled French aristocrat the duc d’Enghien in 1804, for example, he charged him with treason, not war crimes. Napoleon’s chief of police famously said the controversial execution was“worse than a crime, it was a blunder”; but no one at the time suggested that either Enghien’s conduct or the execution itself amounted to war crimes. Napoleon’s regime levied the same treason charges when it executed Don Giovanni Batista, the Marquis Rodio, in Calabria in southern Italy in 1807, and again when it executed guerrillas on the Spanish Peninsula in 1808. Napoleon claimed to exercise authority as the new sovereign (Spain) or as the military governor of territory occupied by the French army (Calabria). His victims were thus treated as traitors and rebels, not as soldiers. But the United States did not claim to be the new sovereign of Mexico, and its small army could not plausibly claim to occupy the vast landscape of Mexico.7
The absence of analogues in the recent history of warfare for Scott’s treatment of the Mexican guerrillas reflected the basic structure of the orthodox laws of war as they had been handed down into the 1840s. For centuries, the law of war had been organized around separating soldiers from criminals, and for at least 100 years, jurists in Europe, Great Britain, and the United States had agreed that the key distinguishing feature—the very definition of a soldier—was holding a commission issued by a state. Those who held such a commission were privileged to commit violence in wartime. They were immune from punishment. Indeed, discussions of the laws and usages of war contained almost nothing about the punishment of crimes by men who carried such commissions.
To be sure, violations of the laws of war were met with forceful sanctions. But such sanctions were not conceived of as punishing an individual offender for an infraction against the rules of warfare. The notion of punishing individual members of the enemy’s armies for violations of the laws of war was almost completely absent. William Blackstone, the English jurist with whom every American lawyer in the first half of the nineteenth century was familiar, wrote that when an individual violated a rule of the law of nations, it was the obligation of the violator’s own government to see to it that he was punished. (As Blackstone put it, violators’ home states were obliged “to animadvert upon them with a becoming severity, that the peace of the world may be maintained.”) The victim government’s recourse, by contrast, was not to the criminal law but to diplomacy and ultimately retaliation.
It was retaliation—not criminal punishment—that formed the eighteenth- and early nineteenth-century law of war’s mechanism for responding to violations. Writers like the American Henry Wheaton and the Swiss Vattel set out elaborate taxonomies of retaliation, ranging from taking an eye for an eye (“retaliation”), to the suspension of privileges for enemy nationals (“retortion”), to the seizure of enemy property (“reprisals”). Wheaton wrote that when “the established usages of war are violated by an enemy,” retaliation was the ordinary tool “to compel the enemy to return to the observance of the law which he has violated.” As one leading international lawyer put it fifteen years after the Mexican War had ended, the law of war had not traditionally been “a Penal or Criminal Law.” It was instead “a code of regulations in between sovereigns.” A half century later, a U.S. Army officer would put the point more bluntly. The law of war, wrote Captain Elbridge Colby, was not a law of crime and punishment but a law enforced by“the cold steel of the bayonet,” by “the cannon that speak the name of Krupp,” and by “the typewriter rattle of automatic arms.” These were the tools of “the litigation of nations under the laws of war.”
There were stray exceptions. The eighteenth-century German jurist Georg Friedrich von Martens had noted as an afterthought that “soldiers who employ means which are contrary to the laws of war” could “be punished” by the enemy. Vattel similarly observed as an aside that if a prisoner of war were “personally guilty of some crime,” the capturing army was “at liberty to punish” him. A few narrow categories of persons—foreign military recruiters and assassins in particular—were said to be subject to punishment. But with the exception of isolated references such as these, Enlightenment-era writers on the law of war had virtually nothing to say about punishing violators of those laws.
The reason why was articulated most forcefully by the French political theorist Jean-Jacques Rousseau. War, he wrote, was “not a relationship between one man and another, but a relationship between one state and another, in which individuals are enemies only by accident.” A state, Rousseau explained, could only have “other States” as enemies because it was “impossible to fix a true relation between things of different natures.” Here was the same idea Daniel Webster had expressed when he opposed criminal prosecution in the McLeod episode. The Mexican guerrillas were engaged in what no one doubted counted as a war. Their targets were usually U.S. combatants. Under Rousseau’s reasoning, they were far better positioned than McLeod had been to argue for immunity from American criminal punishment.
YEARS LATER, Scott invoked the right of retaliation in defense of his military commissions. It was “a universal right of war,” Scott observed, “not to give quarter to an enemy that puts to death all who fall into his hands.” But Scott’s military commissions and councils of war did not fit the concept of retaliation very well at all. Retaliation was not an individualized practice but a collective one. It was an act of one nation aimed at an enemy nation. It could entail taking measures against enemy prisoners and enemy property, or even (in extreme cases) enemy noncombatants.
In the century before the Mexican War, however, the law of retaliation had begun to change. James Kent of New York, writing in his wildly popular 1820s book on American law, explained that in modern warfare retaliation “ought to be confined to the guilty individuals, who may have committed some enormous violation of public law.” It would be inconsistent with the spirit of the age to put “innocent prisoners, or hostages, to death” merely because “the community, of which he is a member,” was guilty of some offense. Once retaliation was so limited, there was vanishingly little space remaining between criminal justice and retaliation. All that remained was for someone like Winfield Scott to push them together.
What Scott and the U.S. armed forces did in late 1847 was to assemble scattered pieces in the eighteenth-century laws of war—the military recruiter, the assassin and the spy, the Enlightenment preference for specific instead of general retaliation—and to build from them a general principle of individual criminal liability for violations of the laws of war. Neither Scott nor Marcy had any deep interest in the coherence of the laws of war for its own sake, or in the conceptual distinctions between retaliation and punishment, or between treating individuals or states as the subjects of the laws of war. Neither man was a jurist. Scott was a hardheaded general in command of thousands of soldiers occupying increasingly dangerous foreign territory. Marcy was a practical politician best remembered today as the man who had once defended party patronage in American government on the ground that he saw “nothing wrong in the rule that to the victors belong the spoils.” But in a culture that for decades had challenged the difference between war and crime, theirs was a natural innovation. Without anyone quite understanding what was happening—without even using the phrase—Winfield Scott and the U.S. armies in Mexico had given life to the idea of the war crime.
NO ONE IN the 1840s seems to have used the phrase “war crime.” The practice of merging the laws of war with the law of crime was too new and too unself-conscious even to have been identified yet. But at least one man grasped the conceptual innovation taking place. He did not like what he saw.
A Nathaniel Currier print from the 1848 presidential campaign. Long thought to depict Zachary Taylor, whose volunteers committed numerous atrocities in Mexico, it is more likely Winfield Scott, whose military commissions in the Mexican War were condemned by his critics.
William Jay, president of the American Peace Society and son of the founding father John Jay, objected that General Scott had dangerously reintroduced the idea of crime into the laws of war. What Scott called “murder,” Jay said, was merely the killing of “any of the guard accompanying a baggage train.” Scott had redescribed the “carrying away” of the property of the U.S. armed forces as “robbery,” but Jay countered that this was precisely the kind of violence that the laws of war authorized. Scott claimed to have developed a new institutional mechanism for enforcing the laws of war. But as Jay saw it, Scott had set aside the laws of war, not vindicated them. (Indeed, in Jay’s view, the Mexican guerrillas typically did “no more” than Americans of his father’s generation had done in the Revolution.) Worse yet, Scott had done so, Jay implied, not out of humanitarian aims but to gain military advantage. By the middle of 1847, guerrilla tactics had become Mexico’s most effective strategy, if not its only strategy. Guerrilla attacks had forced Scott to deploy more than a quarter of his troops—some 5,000 soldiers—to guard his supply lines. Executing guerrillas had allowed Scott to reallocate troops from the rear to the front.
Scott himself had nothing but scorn for Jay and the peace societies. War, Scott believed, was “the natural state of man.” He called the peace societies “moral distempers,” the “cankers of a long peace and a calm world,” and listed them alongside anti-Masonry, constitutional nullification, and Mormonism as the United States’ most glaring social disorders. In response to Jay’s objections, the general observed contemptuously that armies had always put to death those who refused to give quarter to their enemies.
The difficulty for Scott was that as far as we can tell it was a bad exaggeration to say that all Mexican guerrilla parties executed U.S. soldiers. Guerrillas rarely spared Mexican wagon drivers. But that was because they treated Mexican nationals acting for the United States as traitors, not soldiers. And while many guerrillas were reported to adopt a policy of offering no quarter to U.S. soldiers, their attacks on stragglers and U.S. wagon trains were often perfectly legitimate (if particularly maddening) acts of war.
Yet if Scott dodged Jay’s criticism, he also failed to own up to the innovative change his councils of war had made. In this sense, Jay understood something that Scott had not fully grasped about the significance of his own orders in Mexico. The councils of war marked a transformation in the orthodox laws of war. The immunity of soldiers on both sides of a war was a strange kind of moral bargain: one that immunized the enemy from the moral sanctions of the criminal law. Scott and his powerful army, however, chafed at the law of war’s awkward covenant. And as it turned out, in this one respect Scott was making the same move Charles Sumner and the peace societies had made before him. Scott, like Sumner, saw crime in what many others deemed to be war.