After months of tangling from afar, Hillary Clinton and Donald Trump will confront each other face-to-face for the first time in Monday night's presidential debate, laying out for voters their vastly different visions for America's future.

The high-stakes showdown -- the first of three presidential debates -- comes as both candidates are viewed negatively by large numbers of Americans, with Democrat Clinton facing questions about her trustworthiness and Republican Trump struggling to convince many voters that he has the temperament and policy depth to be president.

Interest in the presidential race has been intense, and the campaigns are expecting a record-breaking audience to watch the 90-minute televised debate at suburban New York's Hofstra University.

Clinton's camp is worried that Trump will be held to a different standard in the debate and is particularly concerned that the notoriously hot-headed businessman will be rewarded for simply keeping his cool.

"We also are concerned that Trump is going to continue to lie," Clinton's campaign manager, Robby Mook, said Monday.

The debate about the debate was still unfolding in the hours before the two candidates were to take the stage.

Clinton backers were publicly pressing moderator Lester Holt of NBC News to fact-check Trump if he tries to mislead voters about his record and past statements. But Trump's campaign pushed back, accusing Clinton's team of trying to put its thumb on the scale by enlisting the media to do Clinton's job for her.

Asked about Trump's incorrect statement that Holt is a Democrat -- he's registered as a Republican in New York -- Trump campaign manager Kellyanne Conway said it wasn't lie, because Trump simply didn't know Holt's voter registration.

"He didn't lie. A lie would mean he knew the man's party affiliation," Conway said on MNSBC.

The centerpiece of Trump's campaign has been a push for restrictive immigration measures, including a physical wall along the U.S.-Mexico border and an early proposal to temporarily bar foreign Muslims from coming to the U.S. But he's been less detailed about other ideas, including his plan for stamping out the Islamic State group in the Middle East, and Conway suggested he'd be similarly coy in Monday's debate.

"You will get his view of how best to defeat the enemy -- without telling ISIS specifically what it's going to be," Conway said, using another acronym for IS.

Clinton, a former senator and secretary of state, is banking on voters seeing her as a steady hand who can build on the record of President Barack Obama, whose popularity is rising as he winds down his second term in office. She's called for expanding Obama's executive orders if Congress won't pass legislation to overhaul the nation's immigration system and for broader gun control measures. Overseas, she's called for a no-fly zone in Syria but has vowed to keep the military out of a large-scale ground war to defeat the Islamic State group.

For Clinton, victory in November largely hinges on rallying the same young and diverse coalition that elected Obama but has yet to fully embrace her. Mook told "CBS This Morning" that she fully understood she still needs to earn voters' trust.

"When she's had the opportunity to talk about not just what her plans are to make a difference in people's lives, but how this campaign is really part of a lifelong mission to fight for kids and families, she's done really well," Mook said.

Trump has tapped into deep anxieties among some Americans, particularly white, working-class voters who feel left behind in a changing economy and diversifying nation. While the real estate mogul lacks the experience Americans have traditionally sought in a commander in chief, he's banking on frustration with career politicians and disdain for Clinton to push him over the top on Election Day.

The billionaire's advisers have indeed been urging him to keep calm on stage, mindful of voters' concerns about his temperament. On Saturday, Trump showed a glimpse of the traits his advisers want to keep in check, announcing on Twitter that he might extend a debate invitation to Gennifer Flowers, a woman who had an affair with Clinton's husband, former President Bill Clinton.

Trump's campaign said the candidate was responding to Clinton's decision to invite businessman and Trump critic Mark Cuban to the debate, and that Trump floated the invitation to remind people of his ability to punch back. By Sunday, his campaign said Flowers would not be attending.

Clinton's team announced Monday that a host of prominent supporters, including Democratic Sen. Claire McCaskill of Missouri and former Obama campaign manager David Plouffe, would be on hand on the debate's sidelines to help her make her case with reporters covering the event.

Clinton has debated more than 30 times at the presidential level, including several one-on-one contests against Obama in 2008 and Vermont Sen. Bernie Sanders in 2016. But Monday's contest will be her first presidential debate against a candidate from the opposing party.

Trump was often a commanding presence in the Republican primary debates, launching biting personal attacks on his rivals. But at times, he appeared to fade into the background, especially during more technical policy discussions -- something he'll be unable to do with just two candidates on stage.

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Associated Press writer Josh Lederman contributed to this report.