A new hero emerges at the final US presidential debate— a mute button.
The first presidential face-off was a chaotic spectacle, but a new hero emerged during the final debate.
Organisers introduced a mute button to Thursday's event between President Donald Trump and Democratic challenger Joe Biden.
The button was controlled by a representative of the Commission on Presidential Debates, to ensure that each candidate would have two full minutes uninterrupted for opening answers on each topic.
The second and final debate got off to a relatively civil start as the two candidates made their opening statements and allowed each other to answer questions from moderator Kristen Welker without interruption.
The two candidates debated for just over 90 minutes at Belmont University in Nashville, Tennessee.
The exchanges included substantive debate on a number of topics including the response to the coronavirus pandemic, immigration and how each would handle climate change as president.
Fox News’ Chris Wallace, who moderated the first meeting, said, “First of all, I’m jealous,” when asked on-air Thursday night what he thought of the tenor of the second debate moderated by NBC News' Welker.
Trump seemed to be on his best behavior. Viewers largely panned his performance in the first debate, in which he repeatedly interrupted Biden.
The most heated sparring was over mutual accusations of graft.
Trump had signalled he'd try to damage Biden with his pursuit of murky accusations that his son Hunter was involved in graft in China and Ukraine while Biden was vice president under Barack Obama.
Trump, 74, did try to raise the issue repeatedly, saying there were "damning" allegations.
He put Biden, 77, on the spot by saying: "I think you owe an explanation to the American people."
Biden flipped the attack, saying no wrongdoing had ever been shown by his family and that serious questions were mounting around Trump himself, including his holding of a bank account in China and failing to publish his US tax returns.
"What they do know is that you are not paying your taxes, or you're paying taxes that are so low," he said, referring to reports on leaked tax data that shows Trump has paid at most $750 in federal income taxes during recent years.
But Biden's heaviest weapon, as throughout his campaign against Trump, was criticism of the president's handling of the coronavirus crisis, which has now killed some 220,000 Americans.
He warned of a "dark winter" coming.
"220,000 Americans dead. If you hear nothing else I say tonight, hear this," Biden said, addressing the television audience. "Anyone who's responsible for that many deaths should not remain as president of the United States of America."
Trump, who was hospitalised with coronavirus this month but has since recovered, hit back by defending his push to reopen the United States as soon as possible, even when medical experts warn that more caution is needed.
"We're rounding the turn. We're rounding the corner. It's going away," Trump said.
"We have a vaccine that's coming, it's ready, it's going to be announced within weeks."
With cases rising rapidly around the country again, a Quinnipiac University poll Thursday found that nearly six in 10 people think the coronavirus is out of control.
Trump and Biden also traded blows on the US leader's friendship with North Korea's Kim Jong-un, which the president said had kept the peace on the Korean peninsula, after Biden and Obama left him "a mess" and the threat of "nuclear war."
"He's talked about his good buddy, who's a thug," Biden said of the young North Korean leader.
"That's like saying we had a good relationship with Hitler before he invaded Europe – the rest of Europe," he said. "Come on."
Whether the showdown at Belmont University in the country music capital can really shift the election is itself up for debate.
"Both candidates clearly learned important lessons from the inaugural debate that was so poorly received," said Aaron Kall, an expert on presidential debates at the University of Michigan.
"But with only 12 days until the election and tens of millions of Americans early voting, it may be too late to fundamentally alter the upcoming election."
Some 45 million Americans are estimated to have joined an unprecedented wave of early voting and polls indicate that almost all voters have already firmly made up their minds. Biden is steadily ahead, with the Quinnipiac University national poll putting him up at 51 percent to Trump's 41.