The presidential campaign took a dark turn here Sunday night as Donald Trump leveled a stream of harsh charges at Hillary Clinton during their second debate, claiming she attacked women who accused her husband of sexual abuse and promising to send the former secretary of state to jail if he is president.

Reeling from the release of a 2005 video showing him crudely bragging about using his fame to force himself on women, Trump sought to salvage his candidacy by going on the offensive against Clinton.

He repeatedly interrupted the Democratic nominee. He lashed out at her with a multitude of falsehoods over her foreign and domestic policies as well as her judgment and character. He called her "a liar" and "the Devil." And as Clinton answered voters' questions in the town-hall-style debate, Trump lurked just an arm's length behind her with a grimace on his face.

Clinton, while mostly restrained, showed flashes of ire at her aggressor. "OK, Donald, I know you're into big diversion tonight," she said. "Anything to avoid talking about your campaign and the way it's exploding and the way Republicans are leaving you."

With the Republican Party in an unprecedented crisis and dozens of GOP officials calling on Trump to step aside since the video's release on Friday, Trump's isolation was laid bare on the stage here when he curtly broke with his vice-presidential running mate, Indiana Gov. Mike Pence, on a central foreign policy issue.

While Pence has described Russia in hawkish terms as a menace in the Middle East, Trump said he disagreed and that they had not discussed Russia's role in the Syrian civil war.

Trump was not alone in answering for his political baggage. Clinton was forced to address damaging leaks of her paid speeches to Wall Street firms as well as the investigation of her use of a private email server as secretary of state.

Trump was energetic but at times confusing, stitching together scattered talking points and often evading the questions, presenting a stark contrast to Clinton's steady if also sometimes halting and lawyerly presentation.

The evening's caustic tone was set when Trump and Clinton refused to shake hands when they met at center stage. Trump was asked at the start of the debate whether he understood that he was effectively describing sexual assault in the newly released video. His voice flat, Trump framed the matter as a distraction from the problems facing the world.

"I'm very embarrassed by it," Trump said. "I hate it. But it's locker-room talk. It's one of those things. I will knock the hell out of ISIS."

Clinton responded: "What we all saw and heard on Friday was Donald talking about women, what he thinks about women, what he does to women. And he has said that the video doesn't represent who he is, but I think it's clear to anyone who heard it that it represents exactly who he is."

Trump dismissed Clinton's comments and unfurled a searing attack on former president Bill Clinton, who watched stern-faced from the audience.

"If you look at Bill Clinton, far worse," Trump said. "Mine were words and his was action. What he did to women, there's never been anybody in the history of politics in this nation who's been so abusive to women. ... Hillary Clinton attacked those same women and attacked them viciously."

Noting that some of Clinton's accusers were seated in the audience as his guests, Trump continued: "What President Clinton did, he was impeached. He lost his license to practice law. He had to pay an $850,000 fine to one of the women, Paula Jones, who's also here tonight. And I will tell you that when Hillary brings up a point like that, she talks about words that I said 11 years ago, I think it's disgraceful."

Clinton refused to litigate the women's allegations raised by Trump, which the Clintons have long denied. "When I hear something like that I am reminded of what my friend Michelle Obama advised us all: 'When they go low, you go high,' " Clinton said, referring to the first lady.

Then Clinton pivoted to a critique of Trump's fitness for office.

"It's just awfully good that someone with the temperament of Donald Trump is not in charge of the law in our country," she said.

"Because you'd be in jail," Trump interjected, referring to his earlier vow to appoint a special prosecutor to investigate Clinton's private emails and handling of classified information.

The debate, co-moderated by Martha Raddatz of ABC News and Anderson Cooper of CNN, was a turbo-charged spectacle in an electric campaign. Trump touched down Sunday in St. Louis a defiant and angry nominee, more isolated from his party than any other in modern times.

Trump spent the weekend mostly hunkered down at Trump Tower in New York, stewing over mass defections from fellow Republicans and taking counsel from a shrinking circle of loyalists. His candidacy has plunged the GOP into civil war and elected officials fearing he could cost them their majorities in both chambers of Congress.

Trump's candidacy was in a precarious state even before Friday's release of the video showing his predatory remarks. After stumbling through the first debate and behaving erratically in the aftermath, Trump fell behind Clinton in most national and battleground state polls.

Trump was combative throughout the debate, accusing the moderators of bias and saying he felt like the debate was "one on three." At one point, as the moderators tried to move the conversation along, Trump snapped at Raddatz and said, "Why don't you interrupt her?"

After an uneven start, Trump seemed to gain confidence as the 90-minute debate wore on. As the discussion moved into policy realms, from health care to the Islamic State, Trump was disciplined in driving the core contrast of his campaign, that he is a change agent and Clinton represents what is wrong with Washington's status quo.

Clinton was challenged by Trump over the leak of her campaign aides' emails containing transcripts of her paid speeches to a variety of financial firms. They showed Clinton talking about taking different positions in private than she did in public.

Clinton defended herself in a halting and lawyerly fashion and brought up former president Abraham Lincoln, who was portrayed as a deal-maker who embraced political compromise in a Steven Spielberg film. She said that portrayal inspired her to make the comment in private.

Trump wanted none of it: "Now she's blaming the late, great Abraham Lincoln," he said, rolling his eyes. "Honest Abe never lied. That's a big difference between Abraham Lincoln and you. That's a big, big difference."

One of the more visceral moments came when a Muslim woman asked a question about Islamaphobia. That led to a discussion of perhaps the most controversial policy proposal advanced by Trump: An immediate and temporary ban on foreign Muslims entering the United States.

When told that Pence said the Muslim ban was no longer operable, Trump said the policy "is something that, in some form, has morphed into an extreme vetting from certain areas of the world." But when Raddatz pressed him for specification, Trump would not say what it had morphed into beyond "extreme vetting."

Clinton noted Trump has said a "lot of dark, divisive things" and used "demagogic rhetoric" in talking about Muslims. Trump, meanwhile, suggested that Clinton's vote for the Iraq War made her culpable for the death of Capt. Humayun Khan, whose parents drew Trump's wrath this summer after speaking against him at the Democratic National Convention.

Earlier in the debate, Clinton brought up Trump's years-long crusade to undermine and delegitimize President Barack Obama by falsely questioning his birthplace in Hawaii.

"He never apologized for the racist lie that Obama was not born in America," Clinton said. "He needs to take responsibility for his actions and his words."

Trump tried to turn the birther issue back on Clinton, falsely stating that she was responsible for starting the controversy. "You actually owe an apology," he said.

Clinton also used Trump's affinity for Russian President Vladimir Putin to cast the Republican nominee almost as a pawn for an adversarial foreign power. Clinton said Russia was "working so hard" to influence the U.S. election.

"Maybe because he has praised Putin," she said, demanding that Trump release his tax returns that would show whether he has any conflicts of interest with Russia or other foreign entities.

"So ridiculous," Trump said. "I don't know Putin . . . I know nothing about Russia."

Also Sunday, Trump seemed to concede that he had avoided paying any federal income taxes for some recent years by taking advantage of tax loopholes and the massive $916 million loss he reported in 1995.

As at the first debate two weeks ago, much of Sunday night's event centered on Trump's temperament. Cooper asked Trump about his penchant for sharing his unfiltered thoughts to millions of followers on Twitter, asking whether his tweets were reflective of a stable person.

Trump, who falsely denied pointing his Twitter followers to an alleged "sex tape" of former Miss Universe Alicia Machado, called his tweeting a "modern form of communication" and "very effective."

"I'm not unproud of it," he said.

In a stunt one hour before the event, Trump invited a small group of reporters to observe what was billed as his final debate preparations. When they arrived in Trump's sixth-floor conference room at the Four Seasons Hotel in St. Louis, they found the candidate in a highly unusual scene - glowering as he sat alongside four women who claimed they had been mistreated by the Clintons.

The quartet included Paula Jones, who accused Bill Clinton of sexual harassment in the early 1990s, and Juanita Broaddrick, who accused him of raping her in 1978.

"Mr. Trump may have said some bad words," Broaddrick told reporters. "But Bill Clinton raped me and Hillary Clinton threatened me. I don't think there's any comparison."

The Clintons have denied the accusations, although Bill Clinton did pay Jones a settlement without admitting or denying her accusation.

Watching as the news conference unfolded was one of the men who orchestrated it, Stephen Bannon, Trump's campaign chief executive and the political provocateur who has long targeted the Clintons as well as the Republican establishment through his conservative website, Breitbart.

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David A. Fahrenthold and Katie Zezima in Washington contributed to this report.