Analysis: She called him a misogynist. He said she should go to jail.

ST. LOUIS — So much for the contrite Donald Trump.

Running mate Mike Pence and other senior Republicans had warned the GOP presidential nominee he had to show regret and humility in the aftermath of a bombshell video that depicted him boasting about his sexually predatory behavior toward women. 

Spoiler alert: He didn’t take their advice. And what followed Sunday night was the most bizarre presidential debate of the television age.

The combative spectacle was launched even before the second debate with Democrat Hillary Clinton began. Trump convened a photo-op, streamed live on his Facebook page, featuring four women who have accused former president Bill Clinton of sexual misconduct in cases dating as far back as his days as Arkansas governor.

During the debate, Trump labeled Clinton the worst abuser in the history of politics after dismissing the degrading language in his video as “locker-room talk” and nothing more.

“It’s just words, folks; it’s just words,” he said. “I apologized to my family; I apologized to the American people.”

For her part, Clinton was measured and cutting.

“With prior Republican nominees for president, I disagreed with them on politics, policies, principles,” she said in her first comments on the tape since it was released Friday. “But I never questioned their fitness to serve. Donald Trump is different.” She called him “not fit to be president and commander in chief.”

She called him a misogynist. He called her a liar.

If elected, Trump said he would instruct his attorney general to appoint a special prosecutor to investigate Clinton’s use of a private email server while she was secretary of State.

“It’s just awfully good that someone with the temperament of Donald Trump is not in charge of the law in our country,” Clinton said.

“Because you’d be in jail,” Trump interjected.

There was an early clue about what was to happen: When they were introduced on stage at Washington University in St. Louis, the two candidates walked to the center of the stage but didn’t shake hands. (They did shake hands at the end.) At times when Clinton was speaking, Trump stood behind her, rocking on his heels and scowling. He repeatedly interrupted her — she sometimes did the same — and tangled with the moderators, ABC’s Martha Raddatz and CNN’s Anderson Cooper.

Forty undecided voters were seated to the sides of the debate stage, but the intimate and empathetic tone that has marked past debates with a town-hall format was missing. The mood was icy and fierce. While several in the audience did pose questions on issues such as Supreme Court appointments and the Affordable Care Act, those concerns were overwhelmed by the flurry of invective — the harshest and most personal rhetoric of any presidential debate in modern times.

Once again, as he has since he launched his campaign more than a year ago, Trump decided to defy the Republican establishment and ignore the conventions of campaigns. He apparently concluded that he would rather risk going out in a firestorm of his own making rather than make the amends customary for a candidate in trouble.

He blasted Clinton as a creature of the political establishment that has led the United States astray. At one point, he referred to her as “the devil.” And he used the seats allocated to him in the debate hall for his wife, his three eldest children and three women who have accused Clinton of unwelcome sexual advances: Juanita Broaddrick, Paula Jones and Kathleen Willey.

The first set of overnight polls indicated that Trump’s core supporters are still loyal to him. But the possibility of expanding his appeal to the swing voters needed to win the White House — moderates, independents, college-educated women — seemed a distant prospect indeed. With his words to a hot microphone on a Hollywood backstage in 2005, Trump created an October surprise the likes of which no previous presidential candidate has survived to win.

Now the question being discussed by senior Republicans is whether Trump's likely defeat ensures a Democratic takeover of the U.S. Senate and even risks GOP loss of control of the House. The furor raises questions about the future of the Republican Party once the day of reckoning comes between Trump’s most fervent supporters and those who have rebuked him.

The cascade of political reaction in the space of a weekend was unprecedented.

The Republican nominee and his degrading language toward women was denounced by the national chairman of his party. The nation’s highest-ranking GOP official, House Speaker Paul Ryan, disinvited him from a chance to share a Wisconsin stage Saturday. South Dakota Sen. John Thune, a member of the Senate leadership, called on him to withdraw. New Hampshire Sen. Kelly Ayotte, in a tough re-election contest, said she would write in the name of his running mate on her ballot. Pence himself released an extraordinary statement saying he didn’t “condone his remarks and cannot defend them ”