The early back-and-forths in this debate showed an interesting dynamic between Haley-Christie and, more subtly, DeSantis-Ramaswamy. Ramaswamy has been going after Haley hard, arguably doing some of DeSantis's work for him, while Christie found himself defending Haley from Ramaswamy's attacks.

What's interesting about this, beyond the fireworks, is where Christie and Ramaswamy supporters might go as this race proceeds, as neither candidate looks to have much chance of winning the GOP nomination (to put it mildly).

Ramaswamy is closely aligned with the Trump wing of the party, which DeSantis is also part of, so some Ramaswamy supporters might look at DeSantis as a preferable option (if they don't want Trump). Meanwhile, Christie's supporters are the least Trumpy, so if he goes by the wayside, they probably would prefer Haley -- a more traditional Republican -- over DeSantis, Ramaswamy and certainly Trump.

-Analysis by Geoffrey Skelley of 538

Christie and Ramaswamy just got into a huge, personal back-and-forth while DeSantis and Haley looked on. Who might voters sympathize with more in that exchange? We can look at each candidate’s net favorability rating for a clue. Ramaswamy has a net favorability rating of +17 points among Republicans, according to 538’s average. That’s not outstanding, but it’s higher than Christie, who is at -34 points. So I’d guess that most Republicans agreed with Ramaswamy more than Christie in that exchange.

-Analysis by Nathaniel Rakich of 538

Christie, pointing his finger at Ramaswamy, said in the first 20 minutes of the debate that Ramaswamy would be voted “the most obnoxious blowhard in America.”

"So shut up for a little while," Christie said.

The former New Jersey governor then offered a defense of Haley, who has so far been the main target of the night.

"He has insulted Nikki Haley's basic intelligence. Not her positions, her basic intelligence," he said, adding, "Look, if you want to disagree on issues, that's fine. Nikki and I disagree on some issues. I've known her for 12 years ... and while we disagree about some issues and we disagree about who should be president of the United States, what we don't disagree on is this is a smart accomplished woman. You should stop insulting her."

Haley turned to Christie and said, “Thank you.”

Ramaswamy went on to criticize both on their foreign policy positions and brought back an attack line he used on Haley at a previous debate: "You can put lipstick on Dick Cheney, it is still a fascist."

-ABC News' Alexandra Hutzler

Haley continues to face blowback over her proposed requirement that every person on social media be verified by their name and banned from posting anonymously -- a position she later walked back slightly.

"She should come nowhere near the levers of power, let alone the White House," Ramaswamy said, calling the position "fascism."

Haley responded, "What I said was that social media companies need to show us their algorithms."

"I also said there are millions of bots on social media right now," she continued. "They're foreign, they're Chinese, they're Iranian. I will always fight for freedom of speech for Americans. We do not need freedom of speech for Russians and Iranians and Hamas. We need social media companies to go and fight back on all of these bots that are happening."

DeSantis pushed back on her characterization of her past comments.

"You can roll the tape, she said, 'I want your name' and that was going to be one of the first thing she did in office," the Florida governor said. "She got real serious blowback and understandably so, because it'd be a massive expansion of government."

-ABC News' Alexandra Hutzler