ST. LOUIS (CN) — Preparations are underway on the campus of Washington University as Republican candidate Donald Trump and Democratic candidate Hillary Clinton prepare to square off in their second presidential debate on Sunday night.
Clinton surged in the polls after their first debate, seen by a record 84 million viewers across the 13 television channels that carried it. That puts pressure on Trump, who hopes to continue the momentum gained from his running mate Indiana Gov. Mike Pence's strong performance in the vice presidential debate earlier this week.
A Wall Street Journal poll shows Clinton leading Trump by 4.3 points, but in Missouri — a conservative stronghold that could prove to be a battleground state — Republicans have a 47.3 percent to 36.7 percent lead over the Democrats.
This debate, the second of three between Trump and Clinton, will be in a town hall format instead of the traditional two podium affair like the first debate between the two.
In a town hall format, the candidates field questions from undecided voters in the audience, as selected by Gallup, and from other social media sources, as selected by the Commission on Presidential Debate, a bipartisan organization that manages the official contests.
The candidates will have two minutes to answer the questions and will have the ability to move around the stage, putting them is close proximity to the audience.
The moderators, CNN's Anderson Cooper and ABC's Martha Raddatz, will then have the ability to draw out the question more for another minute.
This format tests both a candidate's style and substance, and is something style of debate that Clinton is far more familiar with.
"There's a lot more interaction, physical interaction," says Judd Gregg, the former New Hampshire senator who helped President George W. Bush prepare for debates. Gregg said a candidate who is too aggressive in a town hall, either with the voters or a rival, "can come across looking really chippy, not looking presidential."
Trump did appear town hall-style meeting in New Hampshire on Thursday night, where he fielded about a dozen of softball questions from a hand-picked group of voters for about half an hour, according to CNN.com.
Trump didn't actually interact with the audience, instead only conversing with a friendly moderator who read the questions —nearly all softballs submitted from the invitation-only crowd. And he publicly scoffed at his aides' previous framing of the event as a warm-up for his pivotal second debate against Clinton.
"This isn't practice. This has nothing to do with Sunday. We're just here because we just wanted to be here," Trump told the crowd in Sandown, which was comprised solely of supporters and local Republican leaders.
"I said, 'Forget debate prep.' I mean, give me a break," said Trump, who mocked Clinton for spending days preparing. "She's resting. She wants to build up her energy for Sunday night. And you know what? That's fine. But the narrative is so foolish."
After his uneven showing in their first debate, Trump's candidacy may rise or fall on his ability to avoid that trap. The Republican repeatedly interrupted Clinton in their opening contest and grew defensive as she challenged his business record and recited his demeaning comments about women.
Those close to Trump have steadfastly insisted that the candidate did well in the first debate, but the hastily added New Hampshire town hall was a tacit acknowledgement that this particular format poses unique challenges and that Trump needed to fine-tune some of his responses to Clinton's barbs.
The debate is scheduled to begin at 8 p.m. CST and is due to last for 90 minutes.
The Associated Press contributed to this report.