Presidential debate 2024 livestream: Trump, Harris face off tonight on ABC News. Watch live.

Kamala Harris and Donald Trump meet on a Philadelphia stage in their likely only matchup before the election for president.

Vice President Kamala Harris and former President Donald Trump now face off for the first, and potentially only, time in 2024 in a high-stakes presidential debate hosted by ABC News. The debate takes place at the historic National Constitution Center in Philadelphia. ABC World News Tonight anchor and managing editor David Muir and Linsey Davis, ABC News Live Prime anchor, moderate the 90-minute primetime debate with no studio audience.

The Harris and Trump campaigns agreed to ABC’s debate rules after weeks of back-and-forth wrangling over live microphones. The Harris campaign initially pushed for the microphones to be turned on the whole time. But the Trump campaign wanted them on only for the candidate whose turn it is to speak. Ultimately, both camps agreed to leave microphones on only for the candidate speaking, similar to the rules in the June 27 CNN debate between President Biden and Trump.

ABC News Presidential Debate Live Stream

Trump won a coin flip toss that determined the order of closing statements. He chose to go last. The candidates will not give an opening statement and will also have to stand behind their respective podiums for the entire debate.

Tuesday night’s debate is the only presidential debate on the schedule. However, the vice presidential nominees, Democratic Minnesota Gov. Tim Walz and Republican Sen. JD Vance from Ohio, are set to face off on Oct. 1 in a debate hosted by CBS News.

An estimated 51.3 million people watched the Biden-Trump debate on June 27, with viewership falling significantly lower than their last debate in September 2020. That 2020 debate had 73 million viewers.

You can watch the Trump-Harris debate across ABC News’s properties, which include ABC News Live’s online streaming, Disney+ and Hulu.

Yahoo will also feature real-time coverage and analysis from our editorial team.

Trump, 78, has struggled to adapt to Harris, 59, who is the first woman, Black person and person of South Asian descent to serve as vice president. The Republican former president has at times resorted to invoking racial and gender stereotypes, frustrating allies who want Trump to focus instead on policy differences with Harris.

The vice president, for her part, will try to claim a share of credit for the Biden administration’s accomplishments while also addressing its low moments and explaining her shifts away from more liberal positions she took in the past.

The debate certainly has the power to swing election odds. The former president has narrowly regained the betting lead over Harris in the presidential election odds. This marks the first time Trump has taken the lead since mid-August when the odds, which U.S. oddsmakers cannot legally participate in, shifted decisively in Harris’s favor following the Harris-Walz ticket's post-announcement boost.

Tonight's debate could be longer than planned. Tonight’s Harris-Trump debate is set to go 90 minutes, but don’t be surprised if it goes a little long. Trump and Biden’s debate in July hosted by CNN was also scheduled for 90 minutes, but ended up running about eight minutes long.