So, November 9th.
Trump loses decisively. But refuses to concede. He insists that "there's something going on", that Hillary stole the W from him just like she did from Bernie, and calls for revolution (incidentally, just like he did after Romney lost).
Now, the news media will laugh and this and call it dangerous. Democrats do the same. I am sure some republicans will. But, do all of them? How many decide that isolating Trump is the right thing to do, and how many decide that they're unwilling to be labeled a co-conspirator with Hillary and get primaried two years down the road? Will Pence concede for Trump, and if so, what consequences will apply.
It's hard to see how the standard approach of labeling the loser the loser, isolating them, and forging a new path will apply here. Trump will not go quietly. He is VERY CLEARLY signaling his willingness to push them blame on Republicans for failing to support him. And the lengths with which he has gone to satisfy the base is on an entirely different level than it was for previous nominees.
It's really easy to see Trump holding on to a lot of power after the election, and it's not clear to be what the GOP can do about it. This is going to be 2009/2010 Palin on some kind of incredible super-steroids.