Ramaswamy came out hitting the other candidates, saying he's the only one who hasn't been bought and sold. When it came to his comments on Ukraine, though, Pence and Haley are hitting back. "You have no foreign policy experience and it shows," Haley said. As Jacob said, his quick rise is drawing attacks, especially on his lack of political experience.
-Analysis by Monica Potts of FiveThirtyEight

Haley tried to go after DeSantis as he was answering a question on Ukraine but it didn't generate the same back-and-forth as with Ramaswamy, and the moderators quickly moved on to another matter. Clearly Ramaswamy -- his lack of political experience and rapid rise in the polls -- has gotten under the skin of the other candidates on the stage and they're going out of their way to take him down a peg even if it means forgoing opportunities against the ostensible polling leader.
-Analysis by Jacob Rubashkin, Inside Elections

The discussion has turned to the U.S. relationship with China. Republicans’ opinion of China has been steadily worsening over the last six years, according to polling from YouGov/The Economist. As of their most recent survey, 91.4 percent of Republicans said China is an enemy of the United States, while just 3.7 percent said China is an ally. The last time more Republicans said that China was an ally than said it was an enemy was April 17, 2017.
-Analysis by FiveThirtyEight

Pence and Ramaswamy got into another spat, this time over Ukraine, with the vice president attacking his rival over Ramaswamy's calls to send military resources to the southern border, not Ukraine.

"Anybody that thinks that we can't solve the problems here in the United States and be the leader the free world has a pretty small view of the greatest nation on Earth," Pence said.

"I have a newsflash. The USSR does not exist anymore," Ramaswamy shot back, referring to the Soviet Union.

-ABC News' Tal Axelrod

In the aftermath of a debate, it can be hard to figure out the actual impact of a viral moment or heated exchange. Here are some data-driven approaches that can help cut through the noise:

First, ignore “instant polls” that ask questions only among people who watched the debate. That group is not likely to represent the feelings of the broader population. Instead, look for post-debate polls — (like ours with Ipsos and the Washington Post) — that ask questions among the same group of Americans both pre- and post-debate.

Second, in the days following the debate, look at data that captures attention to candidates, such as trends in search results or media coverage, to determine which candidate made the biggest splash. Media attention is crucial for candidates who aren’t well known to gain traction in the polls and with donors.

Finally, look for changes in horse-race polls in the week or two after the debate. There is a lot of noise in primary polls (especially this time around) and it can take some time for changes in public opinion to be reflected in our polling average.

The big thing to remember is that what’s important to journalists and television pundits may not be what’s important to the public, and we have to wait for pollsters to ask them how they feel.

-Analysis by G. Elliott Morris of FiveThirtyEight