Brian Doherty at Reason has tied himself in a knot here:
One cannot take anything good Trump has ever said seriously (he's a liar and authoritarian twat), but all the bad things he has ever said, joked about, or supported must be 100% incorporated into one's opinion of his. Strange asymmetry.
Also, of course, then we get:
Fear about the wild evils the Other Side will commit if in power are a very strong motive power in American politics today. It's rhetorically effective because you can't win an argument about how some group in power will behave with reason or evidence; such claims can only be judged with common sense and ratified by time.
If so... why are you writing, sir?