They "control it", in a way that Trump has exposed just how desperate they are to keep him out. We've never seen anything like this before. In the last 2 elections the establishment Republicans ran retreaded deadbeats no one wanted. (McCain & Romney). The Republican voters stayed home, while Obama won, and they, (establishment Republicans), kept control of their losing party that most everyone could no longer stand the stench of.
Now Trump has come in, kicking the tables over and firing everyone up. And in the process bringing in millions of new voters. He is the answer to the Republicans problems, yet they treat him as if he is the problem. People are asking themselves why? The answer is obviously apparent. He'll kick their asses out the door if and when he gets in. All these establishment old farts like McCain, Romney, McConnell, Graham, and the rest of these washed up do nothings, are all going to have to either retire from politics, and or get real jobs.
They hate that, so they're throwing tantrums and acting like assholes in the process. All of them. This pushes Trump even higher, because now the voters want to get even by ramming Donald J. Trump right up their asses. I hope to hell they succeed!