The legal destruction of slavery was the product of presidential proclamation, congressional legislation, and eventually constitutional amendment, but the practical destruction of slavery was the product of war, what Lincoln called war’s “friction and abrasion.” Slaves took advantage of the upheaval to reach for freedom. Some half a million of the South’s 4 million slaves ran away to Union military lines. More than 100,000 runaways took up arms as federal soldiers and sailors and attacked slavery directly. Other men and women stayed in the slave quarter, where they staked their claim to more freedom.

War disrupted slavery in a dozen ways. Almost immediately, it called the master away, leaving the mistress to assume responsibility for the plantation. But mistresses could not maintain traditional standards of slave discipline in wartime, and the balance of power shifted. Slaves got to the fields late, worked indifferently, and quit early. Some slaveholders responded violently; most saw no alternative but to strike bargains—offering gifts or part of the crop—to keep slaves at home and at work. An Alabaman complained that she “begged . . . what little is done.” Slaveholders had believed that they “knew” their slaves, but they learned that they did not. When the war began, a North Carolina woman praised her slaves as “diligent and respectful.” When it ended, she said, “As to the idea of a faithful servant, it is all a fiction.” Whites’ greatest fear—retaliatory violence—rarely occurred, but slaves gradually undermined white mastery and expanded control over their own lives.