When Trump wins he should tell them to leave the GOP. Some are waiting to pull a Jim Jeffords. Make it easy for them. Bring the SCOTUS judges down to 6 by not replacing them. Shut down the gov’t? Trump doesn’t care.
He's not really a Republican anyway. He's an independent who used the Republican primary process to get on the ballot. That's how they ended up with a Republican presidential candidate who is 100% opposed to several key planks of the national Republican platform (open borders and free trade, for example).