It was a Yankee inventor named Eli Whitney who gave the strongest impetus to Southern slavery after the American Revolution. Six years after the Constitution was ratified, Whitney created the cotton gin, a device that separated seeds from fiber in the short-staple cotton grown in inland areas of the South. Before Whitney’s invention, cotton seeds had to be separated from cotton fiber by hand, a timeconsuming task that had limited cotton cultivation in North America. After Whitney’s invention, large and small cotton plantations became practical, even with the expense of slave labor. Within eight years of the first cotton gin, the South increased its annual export of cotton from 150,000 tons to 17 million tons. As the Deep South states of Alabama, Mississippi, Louisiana, and Texas entered the Union, cotton became the South’s most important crop and the country’s most important...