After generations of loyalty and despite the general stability of Americans’ party identi- fication in adulthood, Southern whites left the Democratic party en masse in the second half of the twentieth century.1 As illustrated in Figure 1, at mid-century white Southerners (defined throughout as residents of the eleven states of the former Confederacy) were 25 percentage points more likely to identify as Democrats than were other whites, a gap that disappeared by the mid 1980s and has since flipped in sign. Despite the massive, concurrent enfranchisement of Southern blacks, who overwhelmingly favored the Democrats from 1964 onward, the resulting shifts in aggregate Southern political outcomes were stark: to take but one example, in 1960, all U.S. senators from the South were Democrats, whereas today all but three (of 22) are Republican.