Rick Santorum won primaries and caucuses in 11 states in 2012, coming in a respectable second in the GOP presidential primary season. And Republicans have a history of bestowing their nomination on the next guy in line, usually an also-ran from the last contest. Yet the former senator from Pennsylvania is rarely mentioned in the already feverish pre-game 2016 chatter among the political commentariat and the donor class. That’s just the way he likes it. Or so he says. “America loves an underdog. We’re definitely the underdog in this race,” he said in an interview Tuesday. Santorum added that being...