Alabama and Mississippi are both genuine three-way races between Mitt Romney, Newt Gingrich, and Rick Santorum. Any of the three could win; any could finish third. Despite solid poll numbers, Romney has never won states where the evangelical vote is as big as it will be in these two Deep South primaries.

Gingrich hopes to win one or both states to revive his flagging campaign. He won the South Carolina primary only to take a back seat to Santorum after losing Florida. He won only Georgia on Super Tuesday. But he is not far behind Santorum in either the delegate count or the popular vote, so a strong showing tonight could give him yet another comeback.

Santorum is currently polling a strong third in both states. But he could pull off an upset with strong support from social conservatives. Alabama Gov. Robert Bentley all but endorsed Santorum earlier today. He’s looking to restart his momentum and protect his status as Romney’s main conservative challenger.