Why did it take so long to end slavery in the United States, and what did it mean that the nation existed eighty-eight years as a "house divided against itself," as Abraham Lincoln put it? The decline of slavery throughout the Atlantic world was a protracted affair, says Patrick Rael, but no other nation endured anything like the United States. Here the process took from 1777, when Vermont wrote slavery out of its state constitution, to 1865, when...