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

Outside of the Trump-critical wing of the Republican primary — featuring Christie and Hutchinson, with major appearances by Pence — most of the presidential field has tip-toed around Trump, careful not to attract his ire. But in the last couple weeks, some candidates have started taking on Trump more directly, jeopardizing their prospects as his running mate.

Trump was already unlikely to name a challenger as his VP pick. Of the 19 unique Democratic and Republican presidential nominees since 1972, only four selected a running mate who had run against them in the same year’s primary. And Trump is even more prickly about loyalty than his recent predecessors.

Last week, we analyzed the tweets of the six highest-polling Republican candidates (other than Trump) in 538’s national polling average. Until recently, DeSantis had hardly acknowledged the former president, mentioning Trump just once since Jan. 6, 2021. But that changed last week, when DeSantis published three critical tweets about Trump. Scott, meanwhile, has largely kept his social media tone neutral toward Trump, but we did see a rare direct criticism on the stump last week, when he said Trump’s suggestion that he’d seek a compromise on federal abortion legislation was the wrong approach. Haley’s tone toward Trump shifted earlier this summer, from cautious to directly critical.

Tonight could tell us whether these recent instances of criticism are the beginnings of a new trend in which the GOP field actually tries to topple the front-runner.

—Analysis by Leah Askarinam of 538