(NewsNation) —Voters are highly anticipating the first and possibly only square-off between former President Donald Trump and Vice President Kamala Harris in a presidential debate that will put them on the same stage for the first time. 

The last debate between President Joe Biden and Trump turned the election on its head, leading to the current president’s exit from the race. He endorsed Harris in his place.

This time the stakes are even higher, debate experts told NewsNation. 

“This is huge,”  Ed Lee III, who served as the senior director for debate deliberation and dialogue at Emory University, said. 

“I don’t think that this debate can be more important in comparison to any other debate that we’ve had in our nation’s history, to be honest with you, and that’s accounting for the last presidential debate that we just had.” 

The viewership is expected to be much higher than the 50 million who tuned into the last debate as many undecided and teetering voters will likely use this forum to make their ballot box decision. 

“This will be the comparison that lots of people make to say yes, this confirms my thoughts about these two candidates,” Lee said.  

Battle of Trump, Harris temperaments

Trump is a known entity when it comes to debates and also comes in with more recent experience, Aaron Kall, director of debate at the University of Michigan, said. 

“People kind of know what they’re getting,” he said. He “kind of goes off the cuff… and I doubt there’s anything he could do to kind of change their opinions or expectations.”

Trump gets a little bit “undisciplined and goes back to the hits and the attacks, which steps on his messages from earlier and causes people then to lose faith. So if he can keep it together for that 90 minutes, that would be helpful.” 

But his debate performances have shown that rarely happens, he said. 

Trump has a modus operandi of making personal attacks on people he’s debating, especially when he feels like he’s up against a wall, Kall said. He’s already done that with Harris’ race and gender. 

This is where Harris will need to stay calm and not take the bait, he said. 

For Harris, it’s “having the discipline just like she has on the campaign trail, to not fall for that trap of ‘oh I’m going to engage him and go try to go tit for tat’  because then the focus of the debate will be about that, and not on some of the issues where she’s a more favorable,” Kall said.

People want to see her presidential temperament in this debate, and there’s a lot of build-up for her to perform well, he said, so in a sense the stakes are even higher for her.

But Trump will need to recognize that he’s not debating Biden, but someone 20 years younger who was a former prosecutor, Kall said. 

What’s at stake for Trump, Harris?

Polls showed that Trump had built a lead over Biden, including in battleground states, but Harris has since edged ahead of the Republican presidential candidate in some national opinion polls.

This may tip the scale because this may be the only time voters can see if the narratives concocted around each candidate hold true. 

Debate performances are really an expectation game and so far each person has been saddled with the “caricature” of who they are, Lee said. 

Harris is seen as someone who shouldn’t be taken seriously by Trump. 

“If that’s that caricature and she shows up and affirms that, then her campaign is really in trouble, but if she works in opposition to that, then she’ll continue to soar,” he said. 

For Trump, the narrative being structured is in many ways similar to what he tried to do with Biden with him being too old and incapable of forming thoughts, according to Lee. 

“This is going to be a knockout punch for Kamala Harris, where she continues to soar, or this will be Donald Trump getting back into this campaign because he convinces the public that, yes, he can be presidential, and that he’s on our side and willing to operate the country in a way that benefits us.”

Previous records that could spill into the debate

Both candidates will need to be mindful about certain topics that voters are highly vetting, experts say. 

For Harris, it could be her changing stances on fracking and Medicare for All. 

Harris co-sponsored Sen. Bernie Sanders’ Medicare for All legislation when she was a California senator and offered a modified plan as the centerpiece of her short-lived 2020 presidential bid but she’s since dropped support. 

As for Trump, his stance on abortion and reproductive rights has seemed to shift in recent weeks. This would be the time for him to plant a flag, Lee said. 

“The salience and the recentcy of Donald Trump’s shifts in talking about abortion and votes in Florida is something that’s much more on the minds of the public.”

Another point of likely contention is the controversial Project 2025 which will be the “boogeyman” of debate, Kall said. 

Harris has made the conservative plan written by right-wing think tank The Heritage Foundation a hallmark of her attacks against him. 

“It would definitely put Trump on the defensive if he had to deal with that,” he said, and Harris, as a prosecutor, will likely bring up all the connections he has to the document.