I saw that over 100 republican foreign policy "experts" signed a letter saying they opposed Trump and would not serve in his administration. I call that a good start, since these are the geniuses that got us mired in Iraq and Afghanistan, want to start WW III over which crooks rule Ukraine and think sending large numbers of troops to Syria is a great idea. They were all behind the Obama/Clinton policy to topple Qaddaffi and create ISIS.
They also want us to be ready to go to war over some islands in the South China Sea, and of course think it is crucial that we keep troops in South Korea, even though it is a rich and powerful country fully able to defend itself.
They think NATO is crucial, even though the threat it was ostensibly created to defend against, the USSR, has been gone for nearly 30 years.
They also are heavily invested in the global free trade scam, which has seen our factory jobs disappear, just as Ross Perot predicted 25 years ago, and our trade deficits skyrocket.
Of course Trump has also drawn the opposition of the living ex republican presidents, ie both Bushes, and all our losing candidates, ie Dole, McCain and Romney. I just hope they get a lot of publicity because all of them are roundly loathed by the party base, ie actual voters as opposed to the donor class, as well as democrats and independents.