I see some conservative pundits framing the contest in terms of Trump the populist v. Cruz the conservative. But Trump is no populist. He may use populist rhetoric, but he doesn't represent the common man. He's not a man of the people or for the people. He comes from old money. His presidential bid is all about self-aggrandizement.
Populism is an ideology. Trump is not an ideologue, but a demagogue. Scott Walker was the closest thing we had to a populist during this election cycle. And Rick Santorum has some populist elements in his message.