When Hillary Clinton and Donald Trump match up at Hofstra University on Monday, it will make for what some are calling the widest contrast of styles ever in a televised presidential debate.

And not just Democrat versus Republican, female versus male.

A studious policy wonk versus a shoot-from-the hip ad-libber. A candidate uneasy with campaigning versus a polished “reality television” star. A person some call stiff versus one often called a loose cannon. Someone who has been in dozens of one-on-one debates versus someone entering his first.

“What’s going to be very readily apparent from the moment they walk onstage is the very strong contrasts between the two,” said Kevin Madden, who worked as a spokesman on Republican Mitt Romney’s 2012 presidential campaign. “Couple that with there is going to be a huge audience watching. This is one of the few moments in campaign where you have the concentrated attention of the entire electorate” and can make an impact.

James Fallows, a former speechwriter for President Jimmy Carter, wrote in The Atlantic that the Trump-Clinton matchup will provide the “most extreme contrast we’ve ever had” since televised presidential debates began in 1960. That Nixon-Kennedy debate, he said, was watched by 36 percent of Americans. The Hofstra debate could set a record for raw audience, but to equal the 1960 audience share, it would have to be viewed by 120 million — or slightly more than the most popular Super Bowl.

For Trump, the GOP skirmishes during the contest for the party’s nomination were exercises in domination and persuasion — call a name (Jeb Bush was “low energy”), make a claim (“I know more about ISIS than the generals” or “We’re gonna build a wall”). And with up to 10 candidates onstage at a time, he never really had to go back-and-forth on an issue or into much detail.

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“Can Donald Trump really go the distance in a long debate with substance? That’s really the question hanging over this entire thing,” said William F.B. O’Reilly, a Republican political consultant who has run numerous campaigns.

O’Reilly said Trump was “able to blow up the [Republican] primary debates pretty easily,” in part because with so many candidates on the stage the “take-away” was usually the most explosive or forceful remark. O’Reilly said Trump “is going to have to change” to succeed in this format.

“When it’s one on one, there’s a lot of information required of you. It can’t be all bombast — there has to be some substance,” O’Reilly said. “That’s going to be the challenge for Trump.”

Through reality TV programs and the GOP debate, Trump has had years of mastering the art of having a conversation with the audience through the camera, said Joel Silberman, a Democratic media strategist and communications trainer.

“He plays to the camera and he knows how to play to the camera,” Silberman said.

That said, Silberman thinks Trump has gotten away, so far, with not having to answer detailed policy questions. He said the Republican “shouldn’t be given a free pass for just showing up.”

Marist College pollster Lee Miringoff said Trump faces questions about his “temperament” and depth of knowledge on issues.

“They key question for Trump has to be: Is he fit to be president?” Miringoff said.

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Trump “controlled the tempo and pace” of the primary debates by going on the attack, said Jack Brown, a body language expert who has scrutinized the candidates on his website, bodylanguagesuccess.com. Brown said Trump should stay aggressive but avoid being a bully.

“I would tell him to interrupt more and talk over her. It’s worked for him,” Brown said.

His advice for Clinton: “Go back to the personality you had when you were secretary of state because you were living in your own skin.”

“When she decided to run, she changed. She was a more likable persona when she wasn’t running for office,” Brown said.

Advice part two: Don’t talk down to people; use more colorful metaphors.

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“She does have to project some humor,” said Nassau County Democratic Party chairman Jay Jacobs, a Clinton supporter. “And she has to look like she’s enjoying the experience — have a little fun in spite of the intense pressure.”

But most importantly, Jacobs said, Clinton must “remain the adult in the room” when Trump attacks or tries to unnerve her. Along a similar line, he said Clinton succeeded in the Democratic debates because “she never allowed Bernie to score any points against her of any consequence,” referring to Sen. Bernie Sanders of Vermont.

“It doesn’t mean she shouldn’t respond to Trump,” Jacobs said. “But respond in the way a parent would to a child that’s been disrespectful.”

Debates at their core, Madden said, “are performances.”

“Bright lights. Big stage. Huge audience and he’s just a better performer than she is,” Madden said. And in the end, even after all three presidential debates have been completed, the public typically remembers “only a moment or two.”

It’s just hard to predict what moment that will be.

His final bit of advice: “The candidate that’s most aggressive wins.”