The second presidential debate may have been the least decorous in modern history, with candidates interrupting each other, exchanging constant glares, repeatedly calling each other liars and, in a startling instance,
Here's what we learned after Sunday's 90-minute encounter between Trump and Clinton:
Lock her up: Trump, who has broken taboos since he announced his candidacy more than a year ago, broke a giant one Sunday. He promised that if elected he would appoint a special prosecutor to investigate Clinton's use of a private server at the State Department, which the FBI declined to prosecute her for. In essence, he joined the people at his rallies chanting, "Lock her up!"
Before Sunday, Trump had resisted their entreaties, insisting the best way to stop Clinton was to defeat her at the polls. No more.
This is a huge step, given that jailing opponents often comes hand in hand with the breakdown of democracies in other nations.
Trump surely knows the threat will get attention. He has a history of making provocative statements as a distraction when his campaign has been in trouble, as it is now. But with more than a year of bold statements, Trump has had to up the ante each time.
"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 in one memorable exchange.
"Because you'd be in jail," Trump fired back.
Such talk fires up Trump's core supporters. But, less than a month before the election, Trump needs to win over less committed voters who may be turned off by such rhetoric.
Trump concedes he gets huge tax breaks: This was the first debate since the New York Times published tax documents showing Trump had taken a nearly $1-billion loss that could have allowed him to avoid paying federal income taxes for nearly two decades.
Trump's response? "I absolutely used it, and so did Warren Buffet, and so did George Soros," he said, casting Clinton's wealthy supporters as complicit.
This will keep the tax issue going for Democrats, who have been relentless in attacking Trump for refusing to release his tax returns and, despite his wealth, apparently paying little in taxes.
Trump and his running mate haven't been talking much: Trump had plenty of disagreements with Clinton over healthcare, taxes and environmental policy. But he also had one with his own running mate.
Trump openly contradicted Indiana Gov.
"He and I haven't spoken, and I disagree," Trump said flatly.
The rift came a day after Pence left Trump to fend for himself this weekend, issuing a highly critical statement after a 2005 video was unearthed showing Trump speaking crudely about women and boasting that as a celebrity he could grope them at will.
In the days since, many prominent Republicans have said they prefer Pence to Trump. The nominee's disparaging tone toward his running mate is not likely to reassure them.
Bill Clinton makes a cameo (sort of): Trump previewed his aggressive intentions more than two hours before the debate began, appearing with three women who have accused former President Bill Clinton of sexual misdeeds and a fourth woman who blamed Hillary Clinton for serving as the court-appointed lawyer for a man accused of raping her four decades ago.
Trump, in his first unscripted appearance since the 2005 video emerged, brought Bill Clinton up repeatedly as he attempted to defend himself, saying the former president had been more abusive to women than "anybody in the history of politics in this nation."
He said he was "embarrassed" by the video of his comments, calling it "locker room talk."
"If you look at Bill Clinton, far worse. Mine are words, and his was action," Trump said.
The accusation matched Trump's theme throughout the night — that politicians may speak better than him but they act worse. He used another version of the argument against Hillary Clinton, saying several times that she made promises throughout her career, but had failed to deliver over three decades in public life.
The candidates want this to end: Both Trump and Clinton looked exhausted, with the reddened eyes of sleep-deprived senior citizens. It's understandable given the pressure both have been under. Trump, who has had a very tough two weeks, lashed out at the moderators repeatedly and complained that he was not getting enough time or an equal distribution of tough questions. Timekeepers showed that he had, in fact, spoken slightly longer than Clinton overall.
There's good news for both of them, and the many Americans who are feeling fatigued from the bruising battle. The election is less than a month away.