Donald Trump. AP He did just enough.

Donald Trump became the first presidential nominee to threaten jail for his political opponent. He told half-truths, quarter-truths, and no-truths. He awkwardly paced and stood behind Clinton, looking at any moment as if he was about to pounce.

But he did not completely implode, and did not have a complete and total breakdown onstage. That's not necessarily good news for Trump, who needed some version of a grand slam to turn around his fortunes after a disastrous weekend. But it is terrible news for the Republican Party.

Trump's debate performance was likely enough to stop the avalanche of Republicans from abandoning his campaign in unprecedented numbers. Republican National Committee Chair Reince Priebus, House Speaker Paul Ryan, Senate Minority Leader Mitch McConnell, and his running mate, Indiana Gov. Mike Pence, will likely continue to publicly support him.

Simply put, Republicans are stuck with their presidential nominee, for better or worse, for the next 29 days.

"It's like in the movies where a guy is riding a horse, gets shot, but the horse is still alive so it keeps running while dragging the corpse in its saddle," one veteran GOP operative put it.

We are at an unprecedented moment in American politics — one that saw a sizable portion of a major party's elected officials stampede away from their presidential nominee with a month to go before the election.

It was almost impossible to keep up with the defections on Saturday. Kelly Ayotte. John Thune. John McCain.

Yet it already seems that Trump's performance Sunday night was good enough to stave off those that matter most: Ryan told his caucus Monday that while he would not defend Trump, he would not outright pull his endorsement. He said the focus would turn to keeping the GOP's House majority, according to a source on the call.

In doing so, Ryan virtually put the nail in the coffin on the presidential race. But even throwing the House majority into question, at this point, means the party's most nightmarish of scenarios is strikingly in play. Meanwhile, Trump continually lashed out over the weekend at those jumping ship — and don't think he won't continue to do so with the leverage he has from his supporters.

Trump fired back Monday within hours, previewing the potential triple-threat catastrophe the party faces: Trump supporters don't vote down-ballot, Republican voters don't vote Trump, and Republican-leaning independents don't show up to vote at all.

And so the question is whether the horse, running around with its lifeless human, will still be standing at the end of a long 29 days.