Newsday's Faith Jessie and White House correspondent Laura Figueroa Hernandez preview the final Presidential debate of 2020 election season. Credit: Newsday / Reece T. Williams

WASHINGTON — President Donald Trump and former Democratic Vice President Joe Biden will square off for their second and final debate on Thursday — a showdown that comes as a record number of Americans have already cast their ballots.

More than 39 million U.S. voters have locked in their votes as of Wednesday, according to the U.S. Elections Project, leaving Trump and Biden to fight for a dwindling share of undecided voters who will be tuning into the debate 11 days before Election Day.

Looking to prevent a repeat of last month’s disorderly debate, the Commission for Presidential Debates, a bipartisan panel that organizes the events, announced changes to cut down on interruptions. Trump and Biden will each be given two minutes to respond to questions while the mic of the other candidate is muted. The candidates will then have the remaining 15 minutes of each six segments to engage in a discussion with both mics on.

The 90-minute exchange comes three weeks after a chaotic first debate and the president’s COVID-19 diagnosis days later. The debate in Nashville, Tennessee, was initially scheduled to be the third in a series, but a town hall-style encounter was canceled last week after the president’s campaign objected to debating virtually because of his coronavirus infection.

The final debate’s moderator, Kristen Welker, an NBC News White House correspondent, said her questions will focus on fighting COVID-19, American families, race, climate change, national security and leadership.

"This is the last opportunity for the candidates to get their messages out to a large viewing audience," said John P. Koch, director of debate at Vanderbilt University. "With only 11 days until the election, in this debate we will likely get a preview of both candidates' closing messages."

Here are five things political analysts say they’ll be watching:

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Will there be a change in tone?

Heading into the final debate, Trump campaign advisers have said they expect the president will strike a less combative tone than the first debate, which generated low marks for him in focus groups and polling.

Despite those stated expectations, Trump, when asked on "Fox and Friends" if he would change his strategy and allow Biden to speak more, said on Tuesday: "It’s OK to, you know, really attack."

Trump campaign advisers have maintained that Biden will stumble if he’s allowed to answer questions without interruption, but Biden surrogates have noted that he emerged the nominee after a Democratic primary season that included 12 prime-time debates.

Biden limited his time on the campaign this past week to focus on preparing for the debate, while members of the president’s prep team from the first debate — former New Jersey Gov. Chris Christie and former White House counselor Kellyanne Conway — have been sidelined after being diagnosed with COVID-19.

Robert Yoon, a communications professor at the University of Michigan who has helped moderators prepare for past presidential debates, said in previous campaign seasons "it's been common to see candidates make a major course correction between debates."

"Despite all that's been said and written about the first debate, I think the president feels he projected strength and that he's his own best debate coach," Yoon said. "His return to the campaign trail after his coronavirus diagnosis seems only to have emboldened the president, so I doubt a kinder, gentler Donald Trump is in the cards. I don't think Biden had a particularly strong debate performance last month, but that was far overshadowed by the president's interruptions and by the critiques of Chris Wallace as the moderator. If we have a repeat of the September debate, there will be a lot of talk about it on cable news the next day, but none of it will affect the trajectory of the race."

Will COVID-19 safeguards be enforced?

Trump has yet to give a definitive answer as to whether he was tested for the coronavirus before arriving at the first presidential debate in Cleveland as was required by the commission.

Asked by a reporter Monday if he planned to take a test before Thursday’s debate, Trump said: "I would have no problem with it."

The Trump family and supporters in the audience for the first debate came under scrutiny for not wearing masks as required of guests, but the president’s daughter-in-law and senior campaign adviser Lara Lea Trump told CNN on Sunday that for the final debate, "if we’re asked to wear masks, we will absolutely do so."

Biden, during an ABC News town hall last week, said he continues to get tested for the virus daily and planned to "abide by what the commission rules call for."

"I think they're going to not let happen, what happened last time, they're going to demand that it's safe," Biden said.

Will muting the mics make a difference?

Yoon, the moderator coach at University of Michigan, said muting the mics "might prevent the home audience from hearing when candidates speak out of turn, but it doesn't prevent an interruption from happening."

"The debate moderator and the other candidate on stage will still be able to hear any interruptions, and the president could still use it as a tactic to keep Biden off-balance, which it did to some extent in the first debate," Yoon said. "If Biden is thrown off stride ... it's actually to his benefit for the home audience to be able to hear what might have caused it."

Vanderbilt's Koch said it will be important for Welker to focus the discussion with follow-up questions when the mics are not cut. She should "let the candidates engage with each other if it is productive and provides useful information, and shut them down and move on if these exchanges resemble those in the first debate."

What are the closing arguments?

Biden enters the debate with an average 8.6 percentage point polling advantage against Trump, according to the poll tracking website Real Clear Politics, but both campaigns have said their internal polling numbers show a much tighter race shaping up in key battleground states than what national polls show.

Trump campaign manager Bill Stepien, in a letter to the debate commission last week, urged it to "rethink" the current topics for the debate and "reissue" topics focused on foreign affairs. Biden surrogates have argued there is overlap between issues that have both a domestic and global impact such as COVID-19, national security and climate change.

As both campaigns aggressively court suburban voters in key battleground states, Lawrence Levy, executive dean of Hofstra University’s National Center for Suburban Studies, said moderate suburban voters recognize the connection between the issues they face at home and global matters.

"Sophisticated suburban swing voters, especially well educated women, definitely see issues like COVID, climate change and even economic growth as both local and global," Levy said. "They also see their children, attending schools and playing on teams that are much more diverse than they or their parents did, and — whether they like it or not — needing to be part of a global community."

Despite the record number of early votes cast "research shows that debates may influence election outcomes at the margins, because of undecided voters," said Koch. "Certainly, because of political polarization and early voting, there are fewer undecided voters at this stage of the election than in the past, but in close swing states the debate may potentially still matter to the outcome."

Will the moderator maintain control?

During the first debate Trump tangled with moderator Chris Wallace of Fox News as he tried to rein in the interruptions. The president told Wallace: "I guess I’m debating you, not him, but that’s OK, I’m not surprised."

Over the past week Trump has stepped up his attacks on Welker, describing her as "unfair" and "terrible" despite one of his top campaign aides praising her selection.

Trump 2020 senior adviser Jason Miller, speaking to Fox News this month, described Welker as "a journalist who’s very fair in her approach" and called her "a very good choice for this third debate."

Yoon, who has advised past debate moderators, said they strive to "avoid falling into a candidate vs. moderator dynamic because that's often exactly what the candidate wants."

"Ultimately, there's really only so much you can do as a moderator to keep order at a debate," Yoon said. "You're not a lion tamer with a chair and a whip."

The final presidential debate

Date: Thursday, Oct. 22

Location: Belmont University in Nashville, Tenn.

Time: 9-10:30 p.m.

Moderator: Kristen Welker, NBC News White House correspondent.

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