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: False

Harris appears to be using a narrow definition of what constitutes a combat zone, because there are U.S. military troops in the Middle East who have come under deadly fire over the last year.

There are currently 2,500 U.S. military troops in Iraq and more than 900 U.S. military personnel in Syria who are on a mission to support local forces to prevent a resurgence by ISIS. While the troops in both countries are mostly involved in an advisory role some of them are also engaged in risky counterterrorism missions against ISIS.

But the real threat to these troops over the past year were the repeated attacks against U.S. bases in both countries by Iranian-backed militia groups that launched more than 170 rocket and drone attacks. But it was an attack on a U.S. base in neighboring Jordan this past January that has proven to be the most costly. Three U.S. Soldiers were killed and 34 others were wounded when a drone launched by those militia groups made it past air defense systems. That attack led the Biden administration to order large-scale retaliatory airstrikes against the Iranian-backed militia groups.