Forget the other candidates.   What about Mike Pence?    This is a guy who came out of nowhere, and (should Trump win) will be a heartbeat away from the Presidency.    Should Trump lose, Pence has leapfrogged to the top of the contenders list for 2020.     The term "Christian Taliban" could be fairly applied to Pence - he has extreme social conservative views.

People used to joke that Trump was a Democratic plant to blow up the GOP.     But it's becoming more likely that Trump was a Tea Party plant to make everybody else in the GOP (including Tea Partier's like Cruz and Pence) look "moderate" by comparison.