It was a lively second debate, with lots of cross talk and arguing and challenging between candidates. Like in the first debate, Trump didn’t come up much. Christie remained the only one to really criticize him, and said he should not be part of the primary process. It’s easy to forget he’s the front-runner when you’re watching these candidates go after each other. They seemed more eager to attack each other than any front-runner in the presidential race.
— Analysis by Monica Potts of 538

We got glimmers of candidates attempting to narrow down the GOP primary field. Haley and Scott sparred over South Carolina politics, Pence criticized DeSantis’ spending in Florida, DeSantis criticized Trump’s stance on abortion, and just about everyone tried to take Ramaswamy down a peg (though that might have been a result of their frustration with him rather than actual political strategy). But what Republicans need in order to wage a credible challenge to Trump’s frontrunner status is to shake up the field, and I don’t know if we saw that tonight. It looked like we might get a little closer to winnowing down the field when moderator Dana Perino asked everyone to write down who they should “vote off the island” — but DeSantis, making a show of being above that sort of petty question, prevented us from getting any answers.
— Analysis by Leah Askarinam of 538

At several points during the second hour of the debate, it got particularly heated between former South Carolina Gov. Nikki Haley and someone she appointed to the U.S. Senate in 2013: Tim Scott.

Haley first went after Scott for not completing what he touted as his economic policy accomplishments.

“I appreciate him. We've known each other a long time. But he's been there 12 years and he hasn't done any of that. He has, they've only given four audits on time,” she said.

Then came a heated back-and-forth before Haley repeated, “Twelve years, where have you been? ... Bring it, Tim.”

The two also fought over Haley’s gas tax in South Carolina.

“​​I would love to finish my conversation with Nikki as it relates to the job that needs to get done. Nikki offered a 10-cent gas tax increase in South Carolina. Talk about someone who has never seen a federal dollar,” Scott said.

Haley then told Scott to do his homework regarding the spending and gas tax in South Carolina. He responded, “just go to YouTube.”

Haley ended the exchange by telling Scott that he was “scrapping right now” (as in scrambling).

“You are scrapping right now, you are scrapping. You know, I fought taxes, I cut taxes, I took care of South Carolina and you know it.”

They then got into a rift over a set of over $50,000 customized curtains for the State Department in the official residence of the ambassador to the United Nations. Haley was the first to live in the new residence.

–ABC News’ Abby Cruz, Gabriella Abdul-Hakim and Isabella Murray

After the moderator asked who should drop out of the GOP race, Christie said he'd have Trump drop out of the race if he had his pick because the former president has been so divisive. Ramaswamy offered an alternate view, arguing that Trump had been a great president, but that the America First movement isn't about one person but about "you," the American people. Once again, Christie differentiated himself by openly hitting Trump, something most of the other candidates shied away from tonight.

— Analysis by Geoffrey Skelley of 538

Several of the Republicans on stage touted their prioritization of border security should they win the presidency.

“What I’ll do on day one is sign an executive order to send the National Guard to partner with Customs and Border Patrol to make sure that we stop the flow of fentanyl over the border,” Christie said first. He expanded his answer to include his plans to fill the “6 million vacant jobs” in the country with legal immigrants.

“This border is going to be a day one issue for me as president,” DeSantis said, also noting that he’d administer the remain in Mexico policy, which requires migrants seeking asylum to remain in Mexico until their US immigration court date.

“We're going to declare a national emergency. Yes, we'll build the wall. We’ll do remain in Mexico,” DeSantis said.

Pence spoke about his role in negotiating the remain in Mexico policy of the Trump administration.

“I negotiated the remain in Mexico policy with the Mexican government. We used economic power to bring the Mexican government to the table. We build hundreds of miles of border wall and despite what's said here today, we reduced illegal immigration and asylum abuse by 90%. And as President of the United States, I can do it again,” he said. “I'm going to be ready on day one to get Congress to step up, secure the southern border of the United States.”

Haley cosigned on the Remain in Mexico Policy.

“Let's go back to Remain in Mexico policy,” she said. “Instead of catch and release. Let's go to catch and deport.”
Ramaswamy said that he was supportive of most of his opponents’ border positions, but that he’d go a step further: he’d end birthright citizenship for the kids of illegal immigrants.

“The Republicans on the stage are on the right side of this issue, militarize the southern border, stop funding sanctuary cities and end foreign aid to Mexico and Central America to end the incentives to come across,” Ramaswamy said.

--ABC News' Isabella Murray