Transformations of American democracy are typically measured by constitutional amendments and federal legislation. But one of the most consequential occurred when Black Americans decided to vote with their feet. During the Great Migration between 1910 and 1970, 6 million of them left the South — where they effectively couldn’t vote for much of that time — for northern and Midwestern states, where they could. Since 1990, though, at least 2 million have returned, a reverse migration that’s reshaping the region’s politics and changing the calculus for the Democratic and Republican parties.
