President Joe Biden reacted to the debate in a post on X early Wednesday morning.

"America got to see tonight the leader I've been proud to work alongside for three and a half years. Wasn't even close," he said.

Biden was in New York City during the debate and will be attending the 9/11 memorial services at Ground Zero later in the day.

A majority of debate watchers think Harris won the debate against Trump, according to a poll taken by CNN and SSRS after the debate.

On who won the debate, 63% of debate watchers said Harris and 37% said Trump.

The poll has a margin of error of +/- 5.3% points.

CNN said that before the debate, respondents were split 50%-50% on who would win.

In June, their instant poll found that among debate watchers, 33% thought Biden won and 67% thought Trump won.

-ABC News' Oren Oppenheim

Harris put Trump on the defensive early on, claiming viewers were "going to hear from the same old, tired playbook, a bunch of lies, grievances and name-calling." She later took digs at his rallies and was the first to bring up his multiple indictments.

Meanwhile, Trump tried to tie Harris to President Joe Biden as often as he could. "She is Biden," he said as he criticized their economic record.

Harris' gender was not broached during the debate, though her race was. Trump doubled down on false claims about her racial identity, though he said he "couldn't care less."

Read more about the debate highlights here.

During the Harris-Trump face-off, both candidates tried to score points by slinging barbs at each other.

Here are some of their sharp jabs:

Trump: “Wait a minute, I'm talking now, if you don't mind, please. Does that sound familiar?”

Harris: “Donald Trump was fired by 81 million people.”

Harris: “He talks about fictional characters like Hannibal Lecter.”

Read more zingers here.

Fact check: Needs context

Conservative allies and former advisors to Donald Trump published a 900-page policy blueprint in April 2023 to help a new Republican administration transition to power. The effort – dubbed Project 2025 – was organized by the Heritage Foundation, a prominent right-wing think tank. It details proposals for staffing the government and restructuring federal agencies, writing regulations, managing the economy and ensuring national security.

Harris claims Trump “intends on implementing” the “detailed and dangerous” plan if he wins a second term. But Trump denies any association with Project 2025, saying on social media in July: "I have not seen it, have no idea who is in charge of it,” and also publicly denounced its substance as “seriously extreme” and developed by the “severe right.”

"I disagree with some of the things they're saying and some of the things they’re saying are absolutely ridiculous and abysmal," Trump posted on social media. Many of the document’s priorities, however, are broadly championed by Trump, including construction of a border wall, mass deportation of undocumented immigrants and banning transgender athletes from women’s sports, among other things.

Dozens of former members of his administration were involved in the project, including former cabinet secretaries and West Wing aides. Many of the same people helped craft the Republican Party platform, ABC News has reported. Speaking at a Heritage Foundation event in April 2022, Trump said: “This is a great group and they’re going to lay the groundwork and detail plans for exactly what our movement will do... when the American people give us a colossal mandate to save America."