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

This was a weird debate, full of interruptions and crosstalk. I'm skeptical anyone actually "broke through" in some huge, game-changing way, and neither of the candidates I closely monitored — Haley or Christie — looked likely to suddenly gain 10 points in the polls next week.

But I did think Haley mostly had a strong night, building on her well-received showing in the first debate. She made the case for a more restrictive approach to border security, dinged Biden for his handling of the economy and immigration, and argued that TikTok is a huge danger to the country. That said, I do wonder if she might've rubbed some viewers the wrong way by saying she felt dumber after listening to Ramaswamy, and with her interruption-filled argument with Scott late in the debate. I say that because of how women are sometimes perceived in those sorts of situations — female candidates in the past have been tagged with misogynistic descriptors like "shrill," for instance. I look forward to seeing the post-debate 538/Washington Post/Ipsos poll to get a better read on how she came across.

As for Christie, he continued to be the one person in the room unafraid of attacking Trump, doing it on a good share of his answers. On the one hand, he's got nothing to lose as the GOP candidate with the worst favorability rating among Republican voters. On the other hand, his dings did occasionally free up opportunities for other candidates to make small digs at Trump without going after the former president as aggressively as Christie did. (For instance, DeSantis took a shot at Trump for adding significantly to the national debt after Christie brought it up.) Christie probably knows that he's got no chance of winning the GOP nomination, but he may also be thinking strategically about how he can help his party avoid renominating Trump. Still, it's going to take some pretty drastic changes in the race for that outcome — Trump winning the GOP primary — to not come to pass.

—Analysis by Geoffrey Skelley of 538