DeSantis is trying a bit there to be the adult in the room, which was effective for him last debate when he derailed a question about climate change, but isn't as effective this time around.

-Jacob Rubashkin, 538 Contributor

Ramaswamy brings up one of his key stump speech issues, ending "birthright" citizenship for people who are born on American soil. It's one of the ideas Trump championed in his campaign and earlier presidency — a bit of showing his hand here as he tacks to be the default Trump replacement in the case that he ends up dropping out of the race.

— Analysis by G. Elliott Morris of 538

Republican primary voters are further to the right on many immigration issues than the general electorate. They support building a border wall, increasing border patrols, and defunding sanctuary cities. In 2020, the last presidential election year, 62 percent opposed a path to citizenship for undocumented immigrations. Ending birthright citizenship, as Ramaswamy says he wants to do, is even more extreme. Candidates tonight are trying to woo those voters tonight with their stances on immigration, but they risk boxing themselves into unpopular opinions should they make it to the general election.
— Analysis by Monica Potts of 538

DeSantis gets a question on China and says he wants a totally new approach to that country. He says that he wants to ban the Chinese Communist Party from buying land anywhere in America, and also says he doesn't want them in our universities. It wasn't clear if he was talking about all Chinese students, or just the Confucius Institutes he mentioned right after.

—Jacob Rubashkin, 538 contributor

Trump maintains a lead of 27 percentage points over Haley, his nearest competitor in South Carolina, according to polls conducted since the first debate. Haley’s average support has grown by 9 points since the first debate, while DeSantis and Scott have fallen.

According to a September survey from Beacon Research/Shaw & Co. Research/Fox Business, 69 percent of likely South Carolina Republican primary voters say they support their first-choice candidate strongly, while 28 percent say they support them only somewhat. Among those that list Trump as their first choice, 86 percent say they support him strongly, while the second-place candidate, Haley, has only 57 percent saying the same.

In a September survey by Monmouth University/The Washington Post, South Carolina primary voters are split on whether the Republican Party should nominate a candidate who agrees with them on major issues (51 percent) or one who can beat Biden (45 percent). Among voters who say they are very or somewhat conservative, selecting a candidate who can beat Joe Biden is more important by a margin of 7 and 11 percentage points, respectively. Voters who say they are moderate or liberal prefer a candidate who agrees with them on major issues by 31 percentage points.

—Analysis by 538