Haley, as a former ambassador, made an impassioned case for the U.S. continuing military and financial aid to Ukraine amid Russia's invasion.

"When you look at the situation, you have a pro-American country that was invaded by a thug," she said. "You want to talk about what has been given to Ukraine, less than 3.5% of our defense budget has been given to Ukraine. If you look at the percentage per GDP, 11 of the European countries have given more than the U.S."

She was interrupted by Ramaswamy, who is opposed to further assistance, and the two had a fiery back-and-forth.

Haley told the political newcomer: "You have no foreign policy experience and it shows."

On Ramaswamy's approach to Putin, Haley said: "This guy is a murderer and you are choosing a murderer."

-ABC News' Alexandra Hutzler

Scott just took a question about national security and turned it into one about immigration, saying our Southern border is the greatest national security threat. Ramaswamy did something similar earlier. If you look at the polling, it’s easy to see why: According to our FiveThirtyEight/Washington Post/Ipsos poll, 36 percent of Republicans identified “controlling immigration” as one of their top issues in the primary — second only to inflation and rising prices.
-Analysis by Nathaniel Rakich of FiveThirtyEight

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

One challenger to Trump has surged ahead — in ad buys, at least. Scott announced an $8 million ad buy this month. The bulk of that, $6.6 million, will go toward TV advertisements in early primary states Iowa and New Hampshire, according to the Washington Post. That’s on top of the $40 million ad buy planned by a super PAC supporting Scott that was announced last month.

Trump and DeSantis, the two front-runners, had dominated in early ad spending. But challengers like Scott have stepped up as they’ve tried to qualify for debates and raise name recognition in early voting states. Super PACs supporting Haley and Burgum have also increased spending recently. Stand for America Fund, Inc., which is aligned with Haley, spent $2.3 million on ads so far in August, while Best of America, which backs Burgum, has spent $2.1 million, according to reporting from NBC News.

Meanwhile, Trump-supporting PACs have spent millions on the former president’s legal fees as the number of indictments filed against him has risen to four. That will leave less money for spending on ads going forward, but Trump remains the top campaign fundraiser.

-Analysis by Monica Potts of FiveThirtyEight