Ramaswamy and Haley traded shots on his Israel and Russia-Ukraine views, with Ramaswamy interrupting Haley and claiming she has been saying misleading things about his proposals on Israel. Ramaswamy has called for winding down aid to Israel after integrating the country more into the region.

"I wish you well on your future career on the boards of Lockheed and Raytheon,” Ramaswamy quipped, referring to the aerospace and defense companies.

Haley struck back: "You have no foreign policy experience and it shows," she said -- and was met with cheers and applause from the audience.

-ABC News’ Abby Cruz

Trump wasted no time attacking other Republican candidates during his pre-taped interview with former Fox News host Carlson.

"I'm saying, do I sit there for an hour or two hours, whatever it's going to be and get harassed by people that shouldn't even be running for president?" Trump said.

The 46-minute interview -- released on Carlson's X account as the GOP debate got underway -- is being seen among the campaigns as an attempt to counter-program the first debate among 2024 Republican presidential candidates on Fox News.

Read more about the interview here.

-ABC News' Lalee Ibssa , Soo Rin Kim and Meredith Deliso

DeSantis expressed support for using the U.S. military to combat drug cartels across the border.

"The president of the United States has to use all available powers as commander in chief to protect our country and the people," DeSantis said.

"When they are coming across, yes we are going to use lethal force," he continued -- a line he's used repeatedly throughout the campaign.

Activists have pushed back that his plan is inhumane and illegal.

-ABC News' Alexandra Hutzler

Martha MacCallum just asked about what to do about migrants already in the United States. In a July poll by The New York Times/Siena College, 39 percent of likely Republican voters say that they supported a “comprehensive immigration reform bill that provides a pathway to citizenship for all undocumented immigrants” in the United States, while 57 percent opposed such a bill. Support was weakest among Trump supporters (29 percent) compared with DeSantis supporters (48 percent) and voters who say they will vote for another candidate (50 percent).
-Analysis by FiveThirtyEight

Perhaps unsurprisingly, the pugnacious Christie repeatedly mixed it up with other candidates tonight. He was critical of Trump, calling the front-runner's behavior "unbecoming" and making him unfit to be president. Christie has a track record of strong debates, having shown in 2016 how he can throw a verbal punch, including his famous takedown of Marco Rubio just ahead of the New Hampshire primary that year. But Christie's criticism of Trump and his high unfavorable ratings among Republicans make his performance unlikely to cause a Christie boomlet in this race.

For Scott, tonight was an opportunity to capitalize on his potential as a candidate who is well-liked by Republicans familiar with him but who is not that well-known. And he largely tried to stay above the fray on most issues, which in theory made sense if he wanted to look like a consensus-style candidate who most Republicans could like. However, that also led to him getting less airtime, as the candidates who engaged each other and freely interrupted were more likely to be on camera. This debate doesn't hurt Scott, but I'm skeptical it helped him much.

-Analysis by Geoffrey Skelley of FiveThirtyEight