If Trump continues to the nomination, which seems more and more likely, Cruz needs to hedge his bets which he is doing by staying close to Trump. If Trump stumbles he has served as a very effective stalking horse for Cruz. Cruz is very smart, just ask Dershowitz, one of his professors.
Why does Cruz keep sinking lower and lower in the polls.
Today I think I got the answer. God is going to put Cruz into the proper frame of mind to say YES when Trump offers him the Veep gig.