Back on July 11th, I tweeted everything you need to know about the Republican presidential candidate field.
Bush & Christie are establishment candidates. Rubio is even more but tries to hide it. Paul's foreign policy is even worse than BHO's. ... Trump is changing the convo. on issues, but low-info. crowd has been convinced he's racist. Carson is somehow even less refined. ... Huckabee: Christian-themed demagogue. Kasich: more establishment. Walker can't stop flirting with the establishment. Perry is empty. ... Serious, principled, polished champions of liberty: Ted Cruz and Carly Fiorina. Those are your two candidates. The rest is a sideshow.
I'd add this: a large portion of Trump's appeal is how much the Republican establishment hates him. Backing Trump is a way for Republican voters to tell Mitch McConnell and John Boehner to go to hell. If the establishment really wanted to cut the legs out from under Trump, they'd go to the press and say, "We don't necessarily like him, but if he's the nominee we can work with that."