Personally I think the guy is a clown and has flipped on so many issues that nobody can really know where he stands. I do think the establishment GOP morons like Boehner and McConell have caused this blowback from frustrated members of the GOP base but there are better, more mature and more intelligent anti-establishment candidates.
30% of the GOP base is throwing a stupid tantrum and Trump is their way of kicking and screaming till they turn blue and pass out.