The ultimate moral blame lies on the Vichy Republicans in Congress.  They know perfectly well that Trump is personally incompetent to be president.  They know he doesn't stand for anything but himself.  They know he will weaken his country's respect and even its strategic position internationally.  They know he has all but destroyed the Republican party as has it has been historically known.

But they also know the implicit deal is that, if he's elected, he'll sign whatever they can put in front of him (and veto whatever they tell him to veto, should enough Democrats and disgusted Republican defectors manage to pass something of their own).  That would give them a chance to lock in their "Republican legislative agenda."  That would give Paul Ryan the "legacy" he so badly craves.  What they're missing is that, someday, their names are going to be carved on a Mount Flushmore: the men and women who abandoned their principles, and their posts, to a tinpot would-be Putin.