Unless either the polls are dramatically off or a terrorist attack occurs, Trump is toast. At that point, Trump's incentives diverge dramatically from those of the Republican Party. He won't care about its continued existence.
During the primary season, speculation ran rampant that the party establishment would block Trump at the convention. I knocked that down at every turn because the Republican Party is a power structure. Those capable of the maneuver were those who had power within that power structure, and the maneuver would risk tearing down the power structure. If you have power within a power structure, you don't risk tearing it down.
Paul Ryan, Mitch McConnell and the rest need to take some actions very soon regarding Trump, or they risk losing their power structure. Then again, they don't have the best record of unifying against Trump in time to save their own hides. Maybe if they had moved in the summer of 2015, they wouldn't be stuck with Trump now.
Back in the Zero-sum politics series, I concluded that there was little likelihood of a real uprising in response to Trump's inevitable whining about the election being rigged. Let's revisit that. Trump will lose. He will whine. Epically. He will have no legal recourse. Random violence? Quite possibly. Organized movements? Not likely, for the precise reasons I gave in the Zero-sum politics series. In particular, Dennis Chong's Collective Action and the Civil Rights Movement. A post-election Trump movement will have no ground-level leaders in the way that the civil rights movement did to solve the collective action problem (see the discussion in the Zero-sum politics series for elaboration, or far better yet, read Chong's book).
So, uprising? No. Violence, though? Disorganized violence, by definition, requires no leadership. And Trump's rhetoric is stirring up a lot of shit. So, trouble may be coming. Violence after the election is bad news for the Republican Party. They need Trump to shut up and go away on November 9. They need peaceful transition to Hillary Clinton with no embarrassments so that they can have a proper midterm swing against her in 2018. They should have a massive seat swing, giving them big gains in Congress. Then, with three Democratic wins in 2008, 12 and 16, the Republicans should really win in 2020, unless they nominate David Duke, or someone like that...
Unless Trump just stirs up so much shit that the Republican Party itself dissolves into civil war. He has no reason not to. And that's the problem. The more post-election mess Trump creates, the more risk there is for the Republican Party. The more skepticism Trump creates about the electoral process, the worse that is for the political system, and the worse that is for everyone, including the Republican Party. The messier elections become in general, the worse that is for the Republican Party.
Everyone, including the Republican Party, benefits from an orderly electoral system with peaceful transitions of power in which voters collectively accept the results of a vote tally and decline to rise up in violence.
November 9, though, is too late for Republican leaders to tell Donald Trump to shut the fuck up and go away. Mike Pence, and other campaign surrogates are telling journalists that the campaign will accept the election results, but that doesn't work when Trump says the opposite.
And here is the other collective action problem. What would really work is for basically the entire House and Senate Republican delegations to tell Trump to accept the election results and show some honor. If it is Trump standing alone, truly alone, then he can be marginalized. The more allies he has, the more trouble he causes. However, any one Republican will have incentives to stand with Trump as a fuck-you to the leadership, just as they have on budget compromise votes.
Yeah, this could keep getting uglier.