Cruz has done well by making the right enemies. Trump is the right enemy here. Cruz is younger and has a future. Rockefeller didn't have a future not because he fought against the party, but rather, that the party shifted away from him.
I find it intriguing that the same people that have fought Cruz relentlessly aren't going to just give up now that Cruz has endorsed Trump. They are going to hang it on Cruz's neck when Trump loses anyways. It's really a no-win situation. The only way to win is not to play. Cruz didn't have to endorse. Cruz could have gone and said, "I'm not endorsing anybody", let Trump crash and burn and then in November say, "I was right to oppose him".
THEN - you go over to all the ex-Trumpists and tell them that Trump is not the way.
Cruz has forgotten that his real enemy is the GOP establishment, not Trump's people. They can huff and puff, but in the end, Cruz has already beaten Perry straight up.
That's not what Nixon did, he reached out to Goldwater's people and tried to form a compromise with them and the other GOP factions, that's the historical precedent, and depending on the type of establishment candidate with the level of funding and support vs. himself, they had a chance of unseating him that was probably too uncomfortable for him to tolerate, and he'd rather just keep his seat safe.
