I am sorry but the Republicans caused this mess upon themselves. They were the ones that courted the fringe and now the nut jobs have taken over...
Trump is running a pretty obvious campaign of populism. You want to hear it, he will say it... Hitler did the same to get to power in Germany in the thirties... Now the establishment party is in trouble, they created this monster(not trump, but the narrative) which this type of candidate can flourish...
The GOP might have to kick him out run a third party guy and give Hillary the White House for America's sake...