I don't normally believe in conspiracies, but I wouldn't put it past the Dems do try and oust real conservatives like Cruz and get a clown like Trump as the nominee. At any rate, Trump is the nominee.
Remember when Rush organized a campaign to keep Hillary in 2008? I wonder how many Pubbies crossed over and voted for her in the Dem primaries. That didn't work, but it probably gave many Dems ideas.