What are political experts watching for in tonight's presidential debate?

Vice President Kamala Harris will face former President Donald Trump in their first debate on Tuesday, September 10. What can we expect from Harris and Trump? 

Harris is "still introducing herself to a lot of people in America," says Democratic strategist Jared Leopold. 

"What she has to do is tell people about who she is and why she's running and contrast herself with Donald Trump, who the majority of people don't like. And people want new options. She just needs to provide herself a good option for people to choose," according to Leopold. 

When it comes to Trump on Tuesday, David Ramadan, a professor at the George Mason University Schar School, says he is in a different boat than Harris. 

"He's been there. He's defined. Everybody knows who Donald Trump is," says Ramadan. "This is Kamala's debate to win or lose, not his." 

Harris and Trump have disputed in the past few weeks over the debate rules, namely whether the microphones will be muted in between answers. 

Trump said last month at a campaign stop in Northern Virginia that he'd "rather have it probably unmuted," even as his campaign pushed to keep the rules the same as the debate between Biden and Trump in June and keep the microphones muted. 

"I didn't like it the last time, but it worked out fine," said Trump. 

Ramadan says there is "no guarantee" that Trump will stay on message during this debate, muted microphones or not. 

"I don't believe he can control himself," said Ramadan. 

While Biden's poor debate performance was the biggest focus in June, Leopold says Trump "messed up a lot" in his first presidential debate against Biden. 

"People forget about it because of what Biden did," said Leopold. "Talking about black jobs, his comments on abortion. That kind of stuff turns people off. And when the spotlight's on him there, against Kamala Harris who's a good debater, I think that's a challenge."