Recent presidential primaries have taken place against the backdrop of a secular realignment in the South, a shift that carries important consequences for nomination politics. In this article, we use statewide exit polls to trace changes between 1988 and 2008 in the Southern Democratic and Republican primary electorates. We find that the Democratic electorate has grown strikingly more liberal, more racially diverse, and less heavily Protestant over the last 20 years. Meanwhile, the Republican Party has solidified into a conservative, almost exclusively white primary electorate. We also identify a growing partisan gender gap in the region. The findings suggest that it will be increasingly difficult for a centrist white Democrat, such as Jimmy Carter or Bill Clinton, to use the South as a launching pad to the nomination. In addition, the growing polarization of the parties' Southern primary electorates will likely continue to widen the ideological distance between the major presidential nominees.