Donald Trump took a scorched-earth approach to trying to right his faltering campaign Sunday night, lashing out at his rival — and even threatening her with imprisonment — during a presidential debate where he confronted the turmoil that's pushing his party toward mutiny.

Before an audience projected to be in the tens of millions, the GOP nominee faced his first public grilling over a 2005 video in which he boasted of sexually mauling women and getting away with tawdry behavior because of his celebrity; Trump responded by angrily accusing Bill and Hillary Clinton of worse misdeeds.

“Never, was there anybody in the history of politics in this nation that was so abusive to women” as Bill Clinton, said Trump, who had three of the former president's accusers in the debate hall in St. Louis as his guests. “Hillary Clinton attacked those same women and attacked them viciously.”

Trump and Clinton did not make any effort to hide their disdain for one another. The two did not even exchange the traditional handshake as they walked onto the stage.

They did, however, shake hands after the 90-minute event.

After starting the debate on an apologetic note over the 2005 video, Trump quickly shed any restraint.

He became riled after Clinton, early on, used the lewd remarks that recently surfaced to spring into all the reasons she believes Trump is unfit to be president.

“If this were just about one video, maybe what he is saying tonight would be understandable,” Clinton said. “But everyone can draw own conclusions at this point. He never apologizes to anyone for anything.”

She accused Trump of attacking Latinos, African-Americans, women and veterans, pointing to the numerous controversies Trump created for his campaign. She said he should be ashamed of himself for the lead role he played in the movement attempting to delegitimize President Barack Obama's citizenship.

Trump responded by repeating the widely debunked claim that it was Clinton herself who launched the so-called birther movement.

When the topic of Hillary Clinton's email troubles arose, Trump made the astonishing and unprecedented move of warning the Democratic nominee that he would use the powers of the presidency to try to put her in jail.

“The thing you should be apologizing for are the 30,000 emails you acid washed,” Trump said, referring to free software Clinton's techs used called BleachBit. “I am going to get a special prosecutor to look into your situation.”

Clinton responded to the attacks on the emails just as she responded to Trump's dredging up the accusers of her and her husband from the 1990s and earlier.

She urged voters to seek out fact-checking organizations — most of which have generally found Trump's claims to be not credible — and insisted she would take a high road.

“Everything he just said is absolutely false and I am not surprised,” she said. “It is just awfully good that someone with the temperament of Donald Trump is not in charge of the law in our country.”

Trump immediately retorted: “Because you'd be in jail.”

With more than two dozen Republican lawmakers and other party leaders rescinding their support since the video surfaced Friday — and the odds against him winning the White House growing steeper — Trump faced a political crisis unlike any candidate has faced in modern times.

Prior to the debate, Trump appeared unbowed, mocking the defectors on Twitter.

“So many self-righteous hypocrites,” he wrote, referring to the Republican leaders and elected officials who withdrew their support.

In a surprise sprung 90 minutes before he faced his rival on stage, Trump appeared near the debate site alongside the women who have accused Bill Clinton of sexual misconduct over the years. They expressed their support for Trump and condemned the former president and his wife.

Clinton faced her own difficult set of questions.

A trove of internal campaign emails posted Friday by WikiLeaks revealed details of the lucrative speeches Clinton delivered behind closed doors after she left the Obama administration in February 2013.

In the excerpts, Clinton said she dreamed of “open trade and open borders” between the U.S. and its hemispheric neighbors, and spoke of the need to maintain “both a public and a private position” on politically difficult issues.

Clinton and Trump were scheduled for their third and final debate Oct. 19 in Las Vegas. Election Day is Nov. 8.

Mark Z. Barabak reported from San Francisco, Evan Halper from Washington and Michael A. Memoli from St. Louis. Associated Press contributed.

mark.barabak@latimes.com