I may be in the minority opinion, but Rush has not chosen a side. He is politically Switzerland in the Cruz v Trump contest. He does say that Cruz is the only conservative in the race, which is a fact. That does not mean that he is anti-Trump. IMO he hopes that Trump can do what he says he will do. Whether it be keeping his promises or is capable of the maneuvering necessary to do so.
His focus is beating the Democrats.......