US President Donald Trump and Joe Biden primed for their final debate Thursday in a televised clash where even the moderator's mute button was unlikely to extinguish the sparks as the two men go at each other only 12 days before the election.
The stakes are high as Trump, 74, and Biden, 77, meet face-to-face for the last time before Election Day on November 3.
Trying to hold on to his sizeable lead in the polls, Biden was expected to want to keep the debate focused on the Covid-19 pandemic that has killed 222,000 Americans against a backdrop of Trump's erratic leadership.
Trump insists that the crisis is on the wane. But with cases rising rapidly around the country as winter approaches, a Quinnipiac University poll Thursday found that nearly six in 10 people think the coronavirus is out of control.
The Republican president, meanwhile, was expected to use the debate to unleash an intensifying personal attack on Biden.
Dusting off smear tactics he used against Hillary Clinton four years ago, he signalled Friday he would go hard on murky accusations that Biden profited from corrupt business relationships involving his son Hunter during the years that he served as vice president under Barack Obama.
Whether the debate staged at Belmont University in Nashville, Tennessee -- starting at 9:00 pm Eastern Time (0100 GMT) -- can really shift the election is itself up for debate.
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.
But the sheer ferocity of an election that has seen a country at its most divided in decades made the debate anything but predictable.
While tension mounted ahead of the debate, organizers at least removed one barrier between the two candidates -- a plexiglass screen installed as a sanitary precaution, given Trump's infection with coronavirus earlier this month.
Trump appears to have made a rapid recovery and with he and Biden both testing negative for the virus just ahead of the debate, the two campaigns agreed to remove the screen.
- Keeping order -
Kyle Kondik, managing director of the political newsletter "Sabato's Crystal Ball" at the University of Virginia Center for Politics, called the debate a last chance to "change the trajectory."
"The stakes are high for both candidates though -- Biden wants to keep the race just where it is, and he doesn't want to provide any late fuel to the Trump campaign."
Trump, though, is a master of tearing up the rules and stirring outrage for political effect.
The first 90-minute Trump-Biden debate on September 29 erupted into an almost non-stop flurry of interruptions, insults and near-shouting.
A majority of the disruption came from Trump. At one point, Biden turned to the president and told him to "shut up."
A second debate planned for October 15 was cancelled after Trump came down with Covid-19 and declined to take part in a virtual debate.
This time, moderator Kristen Welker, a White House correspondent for NBC News, will be armed with a mute button to ensure that each man can speak uninterrupted during portions reserved for statements.
She has selected six topics: fighting Covid-19, American families, race in America, climate change, national security and leadership.
"Hopefully he'll play by the rules," Biden said on his way to Nashville.
But Trump set the tone earlier Thursday by attacking Welker, calling her "no good" and a "radical Democrat."
And he showed his willingness to play hardball by inviting as a guest to the debate Tony Bobulinski, who says he was a former business associate of Hunter Biden and believes Joe Biden profited from his son's business in China.
Biden has denied any wrongdoing and calls the reports about his son a last-ditch attempt to change the course of the election with dirty tricks.
Trump was impeached last year by the lower house of Congress for abusing his office in pursuit of compromising dirt on Biden's family. He is also accused of multiple sex crimes and has seen numerous key associates during his presidency go to prison or be indicted.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)