More than a dozen states vote Tuesday, and almost 1,500 delegates are at stake. It's the biggest day of the 2016 presidential election, and it could be pivotal.
Seven Southern states are voting Tuesday — Alabama, Arkansas, Georgia, Oklahoma, Tennessee, Texas and Virginia. That means on the Democratic side, black voters will play a pivotal role. (Six of those states, except Oklahoma, have significant black populations in Democratic primaries.) But for the GOP, those same Southern states mean a more socially conservative, more religious electorate.