Donald Trump and Hillary Clinton answer questions during the third and final debate at the University of Nevada at Las Vegas.

Oct. 19, 2016 Donald Trump and Hillary Clinton answer questions during the third and final debate at the University of Nevada at Las Vegas. Melina Mara/The Washington Post

The third and final debate Wednesday marked the beginning of the end of a presidential race that most Republican leaders cannot wait to forget. But the party’s Donald Trump-driven divisions will not cease on election night.

The axis of furious conservative activists and hard-right media that spawned Trump’s nationalist and conspiratorial campaign is determined to complete its hostile takeover of the GOP, win or lose.

Trump’s insistence that the election will be “rigged,” which he again suggested at the debate, has only stoked the specter of a grievance movement that will haunt Republicans for months and years to come — threatening to leave the longtime norms of American politics shattered and Washington paralyzed by his followers’ agitation and suspicion.

“What I’m saying is that I will tell you at the time,” Trump said Wednesday, refusing to say whether he would accept the result of the election as legitimate. “I’ll keep you in suspense.”

The first post-election target for the grievance movement is likely to be House Speaker Paul D. Ryan (R-Wis.), who has drawn Trump’s wrath for not supporting him more fully. Trump’s backers, both inside and outside the House Republican caucus, are already talking about a takedown.

Here are key moments from the third and final presidential debate between Democrat Hillary Clinton and Republican Donald Trump, Oct. 19, in Las Vegas. (Sarah Parnass/The Washington Post)

Fox News host and Trump ally Sean Hannity said in an interview after the debate that Ryan was a “saboteur” and “needed to be called out and replaced.” Hannity said he would actively urge hard-line conservatives to launch bids against Ryan.

That follows Trump’s blistering attack last week on Ryan as “weak and ineffective” and a rush of anger on social media in which Ryan and other elected Republican officials have been cast as enemies.

[At third debate, Trump won’t commit to accepting election results if he loses]

For top Republicans, the challenges could be staggering in the aftermath of a Trump defeat, as polls show is probable. Their numbers are likely to shrink in both chambers of Congress, and they would have to navigate a Hillary Clinton presidency with constant questions about their loyalties and scorn for any attempts at bipartisan governing.

“The revolt that has been going on in the Republican Party, that brought Trump to where he is, is not going away. If anything, it’s going to intensify,” said Patrick J. Caddell, a veteran Democratic strategist who advises Breitbart, the Trump-aligned website, on polling.

“Republicans are living in a dream world if they think their voters are going to stop fighting the political class,” Caddell said. “What has happened will metamorphosize. The American people will not go gently into the good night of obscurity.”

At the fore of this conglomeration is Stephen K. Bannon, the former head of Breitbart who has become Trump’s most influential confidant. Bannon encouraged the candidate’s claims of voter fraud and references to a deeply corrupt global conspiracy of international banks and corporate-friendly politicians.

The Fix’s Aaron Blake breaks down the key moments of the third presidential debate on Oct. 19 between Hillary Clinton and Donald Trump. (Bastien Inzaurralde/The Washington Post)

Bannon has been a prominent backer of political assaults against Ryan and other Republican leaders over the past decade from the party’s fringes — boosting primary challengers against Ryan and others, and warning against compromise on hot-button issues such as immigration. But with the fringes of the GOP now managing the Republican nominee, a retreat is far from likely.

Bannon’s friends say he has become emboldened during his time with Trump, and that they expect him to work with his network of allies, super PACs and websites to battle Ryan and the Republican establishment throughout 2017 as that wing of the party tries to rebuild the GOP brand.

“What the media misses is the amount of anger that’s out there. Trump didn’t create that,” Bannon told CNN late Tuesday in a rare interview.

When Bannon was pressed about whether Trump would start a television network should he lose, Bannon grinned and said, “Trump is an entrepreneur.”

It is not just Breitbart that stands ready to claim the party’s future as its own. The conservative media, once dominated by high-minded journals and Fox News, has been supplanted by a galaxy of websites such as Infowars, which is led by Alex Jones, who calls the Sept. 11, 2001, terrorist attacks an inside job. In a sign of his growing influence, the Clinton campaign featured Jones this month in an attack ad against Trump.

Articles on those outlets have found their way into Trump’s speeches and have been spread widely across platforms such as Facebook and Twitter, often building into a frenzy that leaves traditional GOP messengers unable to shape the consensus within their own party.

“Forget the press — read the Internet,” Trump told his supporters Tuesday in Colorado. “Study over things,” he added. “Don’t go for the mainstream media.”

[Inside Donald Trump’s echo chamber of conspiracies, grievances and vitriol]

Not every conservative, however, expects Trump to maintain the kind of power he has exerted over the past year, especially if Clinton wins in a dominant way.

“If Mr. Trump does not win, he will retire to projects like other developers do, working on things more to his liking, and Paul Ryan will be one of the undisputed elder statesmen,” predicted Hugh Hewitt, the conservative talk-radio host. He cited Senate Majority Leader Mitch McConnell (R-Ky.) as another GOP leader who would step to the fore to reclaim the GOP.

“Main Street Republicans, small-business owners, people who believe in free markets,” Hewitt said, “will revert to the Ryan-McConnell wing gladly. . . . We’ll revert to the mean, not the Trump banner.”

Rick Wilson, a Republican strategist who is advising independent presidential candidate Evan McMullin, said that “it’s hard to see a mass Trumpism movement without Trump.”

“After 2008, there was a little Sarah Palin cult that has lasted, but it hasn’t changed the party,” Wilson said. “I see the same thing with Trump: a group of die-hards building a whole mythology about, ‘He was betrayed.’ Ryan is going to have to crack the whip and instill some discipline to remind these guys that they don’t run the party.”

Within Trump’s inner circle, the view of the nominee and his place in political history is far different and could have sweeping consequences for Republicans, in particular with how the party frames its agenda. Trump is described by his close advisers as a figure whose power comes from beyond the party and whose politics may not need one.

Trump and Bannon have spoken increasingly about Trump being the American incarnation of Brexit, the successful grass-roots campaign in Britain for the country to withdraw from the European Union. That makes Trump less a candidate along the usual right-left spectrum and more of an outlier who whips up outrage over globalization.

“Believe me, folks. We’re doing great. If we keep our spirit and go out and win, this is another Brexit,” Trump said Tuesday in Colorado, where he also described the media as colluding with Democrats and Republicans.

At the debate Wednesday, Trump showed flashes of traditional Republicanism with his answers on gun rights and the Supreme Court, and was unusually restrained for the opening hour of the debate. But the combative personality at the heart of his bid was nevertheless at the center of his performance.

He mentioned a report by Project Veritas Action, a provocative conservative activist group, as evidence of the Clinton campaign being responsible for “violence” at his rallies. He called the Clinton family’s charitable foundation a “criminal enterprise.” He said the media is “poisoning” voters’ view of him.

Everything is “rigged,” Trump said, from the economy to policymaking to the election itself.

It was a reflection of who Trump is and what his Republican Party looks like now — and, quite possibly, for some time to come.