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

Trump maintains a lead of 28 percentage points over his nearest competitor in South Carolina, according to the latest polls.

Haley and Scott, the two candidates from South Carolina, are both polling higher in South Carolina than they are nationally, according to our polling average. Trump is polling about 7 points lower in South Carolina than in national polls.

Only one pollster, the Manhattan Institute has tested the favorability of Republican candidates in South Carolina since July 1. That survey found Scott and DeSantis had the highest net favorability in the state (+56 and +55 percentage points, respectively), and Trump and Haley close behind (+39 and +33 points, respectively). Pence had a net favorability of +1 point, and Christie was underwater by -36 points.

Economic issues are most important to Republican primary voters in South Carolina, according to a July survey from Fox Business/Beacon Research/Shaw & Co. Research. Fifty-one percent of Republican voters said economic issues would be most important for deciding their vote. Twelve percent each said immigration issues, social issues and foreign policy were most important.

In an August survey by National Public Affairs, 40 percent of South Carolina Republican voters said that Trump wouldn’t lose their support even if he did not show up to the debate. Twelve percent said that they support Trump, but if he didn’t debate they would be open to or definitely supporting someone else, 32 percent said they wouldn’t vote for Trump regardless, 9 percent said they probably wouldn’t watch the debate anyway and 6 percent were unsure.

-Analysis by FiveThirtyEight