Articles in this space traditionally focus on issues or problems confronting the historical profession. There is no rule against an essay that deals with history rather than with historians, however; so this month I will look at a currently controversial historical question: preventive war. The United States has been involved in two previous wars of this nature in which it was the target instead of the instigator of a preventive attack: the Civil War and World War II. The fate of the nations that launched these attacks was not a happy one.

The secession of seven southern states in 1860–61 was a preemptive act to forestall the anticipated threat to slavery and white supremacy presented by the incoming Republican administration of Abraham Lincoln. The election of Lincoln, declared an Alabama newspaper, "shows that the North [intends] to free the negroes and force amalgamation between them and the children of the poor men of the South." If Georgia remained in a Union "ruled by Lincoln and his crew," warned a secessionist from that state, "in TEN years or less our CHILDREN will be the slaves of negroes." Jefferson Davis insisted that Confederate states had seceded "to save ourselves from a revolution" that threatened to make "property in slaves so insecure as to be comparatively worthless."

Southern moderates tried in vain to persuade their hotheaded colleagues to give the Lincoln administration a chance to fulfill its promise of nonintervention toward slavery in the states. Wait for an "overt act" against southern rights before taking the drastic step of secession with its risk of civil war, they implored. But fire-eaters insisted that the South could not afford to wait until the North loosed another John Brown or other weapons of mass destruction. "If I find a coiled rattlesnake in my path," asked an Alabama editor, "do I wait for an 'overt act' or do I smite him in his coil?" When moderates pointed out that "it will be several years before Lincoln will have control of the sword and the purse through the instrumentality of Congress," that only "furnishes additional arguments for action NOW," maintained a Mississippian. "Let us rally before the enemy can make good his promise to overwhelm us. Delay is dangerous. Now is the time to strike."

Strike they did, at Fort Sumter on April 12, 1861. Lincoln had notified South Carolina's governor of his intent to resupply the fort's garrison with provisions only—not reinforcements. But Confederate authorities decided to preempt this peaceful mission, which they twisted into the first step of an attack, by attacking first and seizing the fort before provisions arrived. "It was obvious," wrote Jefferson Davis, "that no time was to be lost in . . . anticipating the impending assault" by shooting first.

Another motive also impelled the preemptive firing on Fort Sumter. Eight slave states had not yet seceded. Even in the lower South the Confederate loyalties of some reluctant secessionists were suspect. An outbreak of actual war would suppress dissent and bring more slave states into the Confederacy. If Jefferson Davis wanted Virginia on his side, said secessionists from that state, "strike a blow! . . . The shedding of blood will serve to change many voters in the hesitating states . . . to zealous [spokesmen] for immediate secession."

So the war came. And for several months, Confederate success seemed assured as Southern arms won important victories. After the battle of Manassas (Bull Run) in July 1861, the Richmond Whig proclaimed, "the breakdown of the Yankee race, their unfitness for empire, forces dominion on the South. We must adapt ourselves to our new destiny." Not to be outdone, the Richmond Examiner declared two months later that military victories had "demonstrated, at once and forever, the superiority of Southern soldiers. . . . The enemy know now that when they go forth to the field they will encounter a master race. The consciousness of this fact will cause their knees to tremble beneath them on the day of battle."

Less than four years later, the empire of this master race lay in ruins. One-fourth of the white men of military age in the Confederate states had died. Two-thirds of southern wealth had been destroyed, including the value of four million slaves who now owned themselves. Burned-out plantations, fields growing up in weeds, and railroads without tracks, bridges, or rolling stock marked the trail of conquering Union armies.

If George Santayana was right when he said that those who are ignorant of the past are condemned to repeat it, Japanese military leaders in 1941 should have paid more attention to the Confederate experiment in preventive war. Just as Jefferson Davis had considered Lincoln's effort to reprovision Fort Sumter an act justifying a preemptive strike, so the Japanese government 80 years later considered the American oil embargo an act justifying the attack on Pearl Harbor. "A nation which does not fight in this plight," Admiral Osami Nagano told the emperor, "has lost its spirit and is already a doomed nation." When the novelist Dazai Osamu heard the news of Pearl Harbor, he exclaimed that he was "itching to beat the bestial, insensitive Americans to a pulp."

In 1861 many southern whites had scorned Yankees as poltroons and cowards, too soft and materialistic to fight. "Just throw three or four shells among those blue-bellied Yankees," said a North Carolinian, "and they'll scatter like sheep." Likewise, Japanese militarists in 1941 were convinced that Americans "lack the will to fight." They were too soft to endure the strains of war. The surrender of 78,000 American and Filipino soldiers at Bataan seemed to confirm that the effete Caucasians and their allies could not stand up to "the leading race."

For almost six months Japanese forces enjoyed almost uninterrupted success, gobbling up the Asian colonies of Britain, France, and the Netherlands as well as of the United States. The Greater East Asia Co-Prosperity Sphere seemed a permanent fact. But less than four years later, two million Japanese had died in the war, Japanese cities lay in ashes, and mushroom clouds rose above Hiroshima and Nagasaki. Japan in 1945 was even more devastated than the American South in 1865. Such were the fruits of preventive war.

—James M. McPherson (Princeton Univ.) is president of the American Historical Association. He can be reached by e-mail addressed to jmcphers@princeton.edu.