Here's how ABC's presidential debate rules work for tonight's Trump vs. Harris showdown

The rules were adopted for the first – and possibly only – debate between former President Donald Trump and Vice President Kamala Harris. The debate on Tuesday in Philadelphia's National Constitution Center is a showdown that could determine the rest of the presidential campaign.

The debate, which begins at 9 p.m. ETwill be moderated by ABC News. There will be no live audience and no opening speeches, according to rules the network published last week.

Candidates will have two minutes to answer questions, two minutes to respond and one minute for follow-up questions and clarifications. The two candidates will also have up to two minutes to make closing arguments at the end.

Harris and Trump are not allowed to ask each other questions. Only the moderators – David Muir and Linsey Davis of ABC – are allowed to ask questions.

The debate lasts 90 minutes and includes two commercial breaks.

Candidates are not allowed to bring notes or props onto the stage beforehand, and they are not given topics or questions in advance.

ABC is allowing other television networks to broadcast the debate simultaneously. CBS News will broadcast the entire debate on the CBS television stations and the CBS News streaming network 24/7, followed by post-debate analysis.

The debate will be the first time Harris and Trump will meet in person.

Debate microphones

There was a Dispute last month between the Harris and Trump camps over whether the candidates' microphones should be muted when it was not their turn to speak. first debateTrump and President Biden’s microphones were muted, which was requested by the Biden campaign team.

The Harris team called for a change to allow open microphones. In a letter to ABC News, they said Harris was “fundamentally disadvantaged by this format, which is designed to protect Donald Trump from direct interaction with the Vice President.”

Although the Harris campaign said the Trump campaign insisted on muting the microphones, Trump declared on August 26 that “I don't care.”

“I probably would have preferred to have it on, but the agreement was that it would be the same as last time,” Trump said. “In this case, it was muted. I didn't like it last time, but it worked out fine.”

The Harris campaign agreed to mute the microphones at the end.

The Harris campaign also told CBS News that it had been assured that the microphones could be pulled if there were significant exchanges between the candidates. A candidate who continually interrupts his opponent will be warned by the moderator and his comments may be relayed to the audience. And if the microphones do not pick up the conversations, a group of reporters who will be in the room could report anything of note.

Notes and debate preparation

The campaigns have taken different approaches to preparing for the debates. Harris traveled to Pittsburgh on Sept. 5 and focused on strategy there, a senior campaign official said. Harris had planned to pepper Trump with questions, but her campaign team had to find a new approach, fearing that her ability to most effectively address the former president would be hampered by microphone restrictions.

The vice president practices with extended mock debates, focusing on policy issues and trying to draw a contrast with the former president. A former Hillary Clinton aide who played Trump in the 2016 mock debate with Clinton is again playing Trump in these sessions. According to one source, the aide even dresses like Trump. Harris has also practiced on a stage with lights to recreate the debate atmosphere, a source familiar with the preparations told CBS News.

While Harris participated in several Democratic debates before the 2020 primaries, this is her first presidential debate, while it is Trump's seventh. Trump told “Good Morning New Hampshire” last week that he had been “preparing for this debate his whole life.”

“You know, I do. I have meetings about it,” Trump added. “We talk about it, but there's not much you can do.”

Sources familiar with the former president's preparations told CBS News that Trump had discussed policy positions with his advisers ahead of the debate, but his preparations were more informal and included conversations with voters and the media.

Closing words

A virtual coin toss was held on Sept. 3, with the candidate who won the coin toss getting to choose the order of closing arguments or podium placement. Trump won the coin toss and chose the order of closing arguments, ABC News reported. The former president chose to make the final closing argument.

Candidates’ podium and stage positions

After the coin toss, Harris was allowed to choose her place on the podium. She chose the podium position on the right side of the screen, ABC News reported.

The rules also state that candidates must stand behind their lecterns for the “duration” of the debate. This rule may remind viewers of the debate between Trump and then-Secretary of State Hillary Clinton in 2016, when Trump left his seat to linger near Clinton in what some viewed as an intimidation tactic.

Aaron Navarro, Kaia Hubbard and Ed O'Keefe contributed to this report.