The other question raised by a Trump victory in South Carolina, though, is why that dynamic would change. In CNN's poll, Trump beats Ted Cruz by a wider margin among evangelical voters than he does among voters overall -- a voting bloc that is supposed to be in Cruz's corner. (In Iowa, where the majority of Republican voters identified as evangelical, Cruz won evangelicals by 12 points. In South Carolina, Trump leads with them by 20.) Trump also leads with conservative voters in South Carolina, although by a smaller margin than he leads overall. If that holds, it's not clear...