Biden vs Trump debate: Where to watch and what to expect - explainer

US President Joe Biden and former president Donald Trump will meet on a debate stage on Thursday for the first of two televised face-offs that could prove critical in their tight rematch race to win the White House in November.

When and where are the debates?

The first debate will air at 9 p.m. ET on Thursday (0100 GMT on Friday) on CNN and be broadcast from an Atlanta studio without a live audience.

It can also be viewed on CNN affiliates without a cable login on CNN.com and is available for simulcast on other US channels.

More than four months ahead of the Nov. 5 vote, the CNN debate will be the earliest presidential debate in modern US history.

Television news channel ABC said it will host the second presidential debate on Sept. 10, also from an audience-free studio.

Who will moderate the debates?

Anchors Jake Tapper and Dana Bash will moderate CNN's debate. ABC's will be moderated by anchors David Muir and Linsey Davis.

Who will debate?

CNN said that only Biden and Trump met the conditions for participating in the debate: appear on enough state ballots to potentially win the presidency and receive at least 15% in four national polls of registered or likely voters.

Independent presidential candidate Robert F. Kennedy Jr did not make the cut.

ABC will also require debaters to appear on enough state ballots to reach the 270 electoral votes and receive at least 15% in four separate national polls.

What are the rules?

In Thursday's 90-minute debate, candidates will appear at a uniform podium, be given a pen, paper and bottle of water and cannot use props or notes, CNN said.

"Microphones will be muted throughout the debate except for the candidate whose turn it is to speak," and moderators "will use all tools at their disposal to enforce timing and ensure a civilized discussion," CNN said.

Biden will be on the podium on the right side of viewers' screens, and Trump will get the last word after a coin toss.

Campaign staff may not interact with candidates during the two commercial breaks, and there will be no studio audience.

ABC's debate rules have not yet been announced.

What to watch for

US presidential debates often draw tens of millions of viewers and have historically determined the course of some races. This time, strategists say there are risks for both candidates, who are locked in a tight race and share low enthusiasm from voters.

Biden, 81, and former president Trump, 78, are the oldest candidates ever to seek the presidency, and viewers are sure to question their cognitive abilities and emotional steadiness.

Trump aides see Biden as prone to verbal slip-ups that could amplify voter concerns about the president's age.

Biden aides think debates could hurt Trump by exposing his volatility and sometimes changing positions on issues, such as abortion.

Biden's campaign is hoping to talk about abortion, and Trump's about immigration, but CNN's moderators will decide the questions.

Topics may include how the candidates would handle challenges posed by persistently high grocery prices, migrants on the US-Mexico border, and the ongoing Israel-Hamas and Russia-Ukraine wars.

Trump's role in the Jan. 6, 2021, attack on the US Capitol, efforts to overturn the 2020 election, and his conviction on 34 felony counts for involvement in a hush-money scheme could come up during the debate, as could the legal woes facing Biden's son, Hunter, who was convicted of lying about his drug use to illegally buy a gun.

What happened last time?

Then-president Trump and Biden debated twice during the 2020 race, with their first exchange devolving into a chaotic shouting match.

According to Nielson Media Research, more than 73 million people tuned in for the first Biden-Trump debate in 2020.

For the second debate, moderators said they would mute each candidate's microphone to allow the other to speak without interruption for the first two minutes of each debate segment. However, the candidates behaved more civilly, and the mute button was not a major factor.

A third debate was canceled after Trump tested positive for COVID-19 and spent three days in a hospital. He declined to participate in a virtual event.

Is this the only debate?

Traditionally, there are three presidential debates. However, no third Trump-Biden matchup has been announced yet.

Vice President Kamala Harris accepted a CBS News invitation for a vice presidential debate on either July 23 or August 13, according to a campaign spokesperson.