As you watch tonight's debate fireworks, keep in mind that Donald Trump is most likely finished outside of the biggest comeback in US political history. He was going to lose anyway, but the GOP was going to definitely keep the House and the Senate would be at worst case a 51-49 Democratic party lead (with that 51st Democrat being Evan F'ckin Bayh).
That was before this weekend, as Ezra Klein explains.
Since Trump won the GOP primary, his party has been working to normalize an abnormal, unpopular, and frankly bizarre candidate. Trump has always had the support of his hardcore fans — but he needed more than that. He needed the mainstream Republicans who didn’t vote in the GOP primaries, or voted for someone else; he needed the independents who didn’t like Clinton, but didn’t trust Trump; he needed the movement conservatives who had entered politics to ban abortion and shrink the government, and who saw little of their crusade reflected in Trump’s history.
And so the party began to coalesce. Mitch McConnell endorsed Donald Trump, and so, eventually, did Paul Ryan. Fox News ended its brief feud with the Republican nominee and closed ranks around his campaign. Reince Priebus dispatched top RNC staffers to work for Trump’s campaign. Marco Rubio offered his support. The messaging was simple, and sober: better Trump than Hillary, better the lunatic who will nominate our judges and sign our tax bills than the liberal who won’t, and even if you don’t believe in any of that, better to support Trump and keep the House then to abandon him and witness the return of Speaker Pelosi.
The process took on its own momentum. To be a Republican in good standing, in recent months, has meant accepting Trump as the party’s nominee, and working to see him elected. As more Republicans backed Trump, the rest had to follow suit. John McCain endorsed Trump, even though Trump had mocked his war heroism. Ted Cruz endorsed Trump, even though Trump tied his father to JFK’s assassination and mocked his wife’s looks.
The effect of all this has been to build a floor under Trump’s vote share, and his media coverage. He might lose the election, but so long as Republicans were able to signal that he’s the guy you vote for if you don’t want Hillary Clinton, he couldn’t lose it that badly — and a three-or-four point loss would probably mean Republicans kept the House and Senate. By the same token, Trump gets plenty of bad press, but so long as the Republican Party stood behind him, he had to be covered as a basically normal candidate, not as a dangerous virus that had somehow infected American politics.
Trump’s army of validators protected him from feeling the force of his own abnormality, of his bizarre comments, of his frequent gaffes, of his erratic behavior. It was a permission structure for voters who didn’t like Trump to vote for him anyway, and it worked. Polls routinely showed that the number of people supporting Trump was larger than the number of people who thought him qualified for the presidency. Voting for Trump, in this context, became what you did if you were a Republican, or if you didn’t like Hillary Clinton. Why? Well, that’s what everyone else like you was doing, too.
And now that’s crumbling. The wave of Republican defections from Trump’s side is the same process that normalized him, but in reverse. Just as Republicans felt more and more pressure to support his candidacy as other Republicans signed on, Republicans — and everyone else — will feel more and more pressure to abandon his candidacy as their co-partisans defect.
We're now at the point where major Republicans are saying "I do not support Trump anymore". It's a no-win situation for them, as his base still plans to vote for the guy in droves. But not quite as many people will vote for Trump now when he was already losing by about five points, and not quite as many people will vote for his party down ballot either.
In other words, a three or four point shift against you when you're up five points (which is what happened to Clinton over the course of September) is a problem. She stopped the bleeding and pushed Trump's gains back. But a swing like then when you're down five points turns a solid but not party-wide loss into an avalanche. (See the Republicans in 2006 and 2008, Democrats, 2010 and 2014.)
That's where we are with Trump. It's John McCain's "The fundamentals of our economy are strong" moment in Florida in September 2008 with the Dow falling 300 points during the course of his speech, the moment everyone realized that the entire Republican party was done eight years ago, and they got stomped for it.
The polls were already bad for Trump. That was before Trump's floor was demolished. His campaign and the entire GOP are in freefall now, and it's only a matter of time before they go splat.