GOP pollster Frank Luntz on Monday spelled out why he firmly thinks the upcoming presidential debate between Democratic nominee Kamala Harris and her Republican rival Donald Trump — on Sept. 10 ― is “everything” when it comes to the 2024 election.

Luntz, during a discussion with CNN’s John Berman, also suggested questions that Trump could ask to maybe confound Harris ― such as on inflation, how to bring it down and “most importantly” using former President Ronald Reagan’s line of, “Are you better off today than you were four years ago?”

“If he asks that question plainly, he will be successful. I don’t believe he has the ability to do so,” Luntz said in an interview highlighted by Mediaite.

The ABC News-hosted debate will see Harris and Trump side by side for the first time. Voters will keenly listen not just to what they say but also focus on their body language, said Luntz.

“Is there contempt? Does someone fold their arms? Do they look at the individual when they’re speaking? Do they seem presidential in their approach?” Luntz said viewers will be taking note of those things.

“For Trump, can he keep quiet? Can he actually listen to a response or does he have to respond to everything?” the pollster continued. “For Harris, does she seem open-minded? Does she seem willing to take in information, not just project?”