DeSantis expressed support for using the U.S. military to combat drug cartels across the border.

"The president of the United States has to use all available powers as commander in chief to protect our country and the people," DeSantis said.

"When they are coming across, yes we are going to use lethal force," he continued -- a line he's used repeatedly throughout the campaign.

Activists have pushed back that his plan is inhumane and illegal.

-ABC News' Alexandra Hutzler

Martha MacCallum just asked about what to do about migrants already in the United States. In a July poll by The New York Times/Siena College, 39 percent of likely Republican voters say that they supported a “comprehensive immigration reform bill that provides a pathway to citizenship for all undocumented immigrants” in the United States, while 57 percent opposed such a bill. Support was weakest among Trump supporters (29 percent) compared with DeSantis supporters (48 percent) and voters who say they will vote for another candidate (50 percent).
-Analysis by FiveThirtyEight

While many candidates onstage have sparred with each other -- including Haley and Ramaswamy swapping sharp words on foreign policy -- Scott has yet to engage with any of the other candidates.

Much of his remarks have almost word for word repeated elements from his campaign stump speech. When asked about China, which he has addressed in other appearances, he pivoted to speaking about the U.S. border.

-ABC News’ Gabriella Abdul-Hakim and Oren Oppenheim

Asked to raise their hand if they would not increase aid to Ukraine, DeSantis did so, saying that "Europe needs to step up. They need to step up and do their job."

He argued: "I would have Europe pull their weight. ... Our support should be contingent on them doing it.

DeSantis -- who had received backlash from some other politicians for seemingly backtracking on support for Ukraine -- pivoted to say that he wasn’t going to send troops overseas but rather down to the Southern border.

-ABC News' Hannah Demissie and Will McDuffie

Haley reiterated her calls for "compassion" when the country debates abortion, though she declined to state whether she would support a federal ban on the procedure.

Haley noted the uphill climb to a federal ban, referencing the 60-vote filibuster in the Senate, but said she would oppose late-term abortions and punishments for women who receive abortions.

"Can't we all agree that we should ban late term abortions? Can't we all agree that we should encourage adoptions? Can't we all agree that doctors and nurses who don't believe in abortion shouldn't have to perform them? Can't we all agree that contraception should be available? And can't we all agree that we are not going to put a woman in jail or give her the death penalty if she gets an abortion? Let's treat this like the like the respectful issue that it is," she said.

-ABC News' Tal Axelrod