The Calculus of Violence: How Americans Fought the Civil War by Aaron Sheehan-Dean (review)

Historiographically at least, the Civil War seems to grow bloodier every year. Recent explorations of soldier and civilian deaths have pushed the war's combined butcher bill upward toward perhaps a million lives lost, in a divided nation of about 31 million people. Yet as bad as it was, it could have been much worse. As Aaron Sheehan-Dean points out in his introduction to The Calculus of Violence, more than 20 million people died in China's roughly contemporary civil war. In Mexico's long Caste War of the Yucatan, 35 percent of the population lost their lives. The American Civil War was somehow simultaneously catastrophic and more controlled. Explaining that apparent paradox is at the heart of Sheehan-Dean's project.

Acknowledging the war's shocking lethality, Sheehan-Dean maintains that nineteenth-century American moral culture, military tradition, and wartime ideology nonetheless combined to limit the killing from spiraling even further out of control. The Lincoln administration fought the war on the foundational belief that Confederates were still countrymen, an assertion that demanded some circumspection. For their part, the Confederates were eager to look like a modern nation-state. Millions of soldiers thus enlisted in conventional armies with clear chains of command and accountability. They fought battles according to long-recognized rules and rituals that permitted surrender and that largely prevented the killing of civilians and prisoners. Threats of equal retaliation, Sheehan-Dean agrees, often worked to deescalate flashpoints. Confronted with ugly incidents, generals wrote each other letters and debated the fine points of law. Meanwhile, the fighting produced new debates among the two governments that led to thoughtful if sometimes ineffective augmentations of the rules of war. Often political leaders refused to go as far as their power allowed. Occupation produced violence but not the show trials and mass killings that appeared elsewhere. Rules mattered, even in the breach. Most important of all, Sheehan-Dean concludes, enslaved African Americans deliberately chose to eschew revenge killings on their way to freedom. A different response might well have produced the racial bloodbath whites on both sides feared.

Yet despite those parameters, the war was bloody enough. Rejecting the widely accepted notion of a war that proceeded steadily from a "soft" phase in 1861 to "hard war" or "total war" at its end, Sheehan-Dean posits waxing and waning waves of violence and restraint at national, regional, and local levels. Much of the staggering casualty total had to do with numbers and the nature of mid-nineteenth century firepower and tactics, but other cultural forces were at play as well, threatening to knock over the barricades. The mid-nineteenth century was a period of growing jingoism around the world, and the people of the divided United States were not immune to casting themselves as noble victims of oppression and anarchy. Even previously pacifist abolitionists embraced the sword, and everyone justified their sides' actions while condemning the enemy. The Confederacy's fateful decision to support irregular warfare unleashed wave after wave of poorly regulated brutality, often directed at civilians. The Union high command responded with an equally lethal counterinsurgency that created a tragic crossfire. Both sides concluded that the established laws of war allowed them to take hostages, imprison civilians, mistreat prisoners of war, depopulate entire regions, execute guerrillas, and seek to limit greater violence through tit-for-tat killing. Emancipation meanwhile led to murderous white-on-black attacks, especially when Confederate troops encountered African American soldiers in the heat of battle. Threats of retribution from Washington lessened but could not prevent racial atrocities. Both sides embraced mayhem at times, but Sheehan-Dean concludes that Confederate racism engendered more abandon.

Sheehan-Dean's learned and measured narrative is grounded in deep research and a thorough understanding of the international and intellectual context. It successfully complicates the familiar linearity of the war's apparent descent into violence. By placing guerrilla...