He’s not a threat to the establishment as much as he is a threat to Constitutionalism.
Yeah, he's not in the establishment's pocket, like Rubio.
He holds no allegiance to anyone, including to the Constitution.
Trump is in it for Trump.
He'll say what he needs to say to win, then do what he wants.
The fact that his supporters so easily dismiss his 60 years of liberalism and seize on his few months of conservative platitudes scares the hell out of me.