Christie criticized the idea that the president could cozy up to Vladimir Putin, noting that all recent presidents have failed to engage Putin by not being tough enough. He then hit Trump for having said that Putin was "brilliant and a great leader." As the night has worn on, Christie continues to be really the only candidate who is bothering to attack the guy who is 40 or more points ahead of every other candidate in national GOP primary polls.

— Analysis by Geoffrey Skelley of 538

Ilia Calderón is asking about sending U.S. troops to Mexico. In a late August/early September survey by Morning Consult, 41 percent of Republicans said they thought that sending U.S. troops to fight cartels in Mexico would be “very effective” at limiting the supply of illegal drugs in the United States. Other strategies had more support among Republicans, such as sending more resources to the U.S.-Mexico border (54 percent), empowering U.S. law enforcement to combat opioids (45 percent), and punishing drug violators in the United States (43 percent).
—Analysis by 538

Haley going after Ramaswamy was a recurring theme in the first debate. They were the standout candidates in our polling last time and there was a lot of speculation about Ramaswamy moving up in the polls — perhaps even surpassing DeSantis. But since August, Ramaswamy has actually lost support, to the point where Haley passed him in our polling average today. It makes sense that they're trading blows again; this seems to be a successful strategy for Haley, and Ramaswamy can't help but take the bait.
-Analysis by G. Elliott Morris of 538

The candidates are discussing support for Ukraine. About half (49 percent) of Republicans and Republican-leaning independents say that vital U.S. interests are not really at stake in the war in Ukraine, according to an August Echelon Insights survey. Thirty-seven percent disagree, saying that if Russia wins, vital U.S. interests and values are threatened. Fourteen percent are unsure.
—Analysis by 538

When debate moderators asked the 2024 GOP candidates about the impending government shutdown, some – including Trump’s closest opponent DeSantis – pivoted to blame the former president and current President Biden for the logjam.

Both men also called out Trump for his absence on stage, noting that he should be answering for himself as the shutdown looms.

"People in Washington are shutting down the American dream with their reckless behavior,” DeSantis said.

“And you know who else is missing an action? Donald Trump is missing an action. He should be on this stage tonight. He owes it to you to defend his record where they added 7.8 trillion to the debt that set the stage for the inflation that we have.”

Chris Christie – one of Trump’s staunchest critics – also admonished the former president.

“If the government shuts down, should voters blame populace Republicans? Very simply everybody who's in Washington, D.C.,” said Christie.

“And let's be honest about this with the voters. You know, during the Trump administration, they added $7 trillion — $7 trillion in national debt. And now the Biden administration has put another 5 trillion on and counting.”

“Donald Trump– he hides behind the walls of his golf clubs, and won't show up here to answer questions like all the rest of us are up here. He puts 7 trillion on the debt. He should be in this room to answer those questions for the people you talk about who are suffering,” Christie said.

–ABC News’ Isabella Murray