“I would absolutely -- absolutely, if they had a plan which showed me, we could get them out safely, you’re damn right I’d send the American Army in there to get our people home and get them home now,” Christie said. The former New Jersey governor accused DeSantis of avoiding the question about deploying U.S. troops to rescue hostages in the Israel-Hamas war after Hamas' terror attack.

-ABC News’ Chris Boccia

What happens when someone rises in the polls? They attract attacks from their opponents. Both DeSantis and Ramaswamy have gone after Haley from the get-go in this debate, putting Haley on the defensive. This isn't really a shock, though, because Haley's poll numbers have been on an upward trajectory, both nationally and in the early states. She also just earned a major endorsement from Americans for Prosperity, a conservative advocacy group, which Haley mentioned when answering about her electability.

Past presidential primary debates have numerous examples of rising candidates facing attacks, but a famous debate from the 2016 Republican nomination race nicely showcases this. Florida Sen. Marco Rubio finished a strong third in the Iowa caucuses, and his campaign looked positioned to potentially compete for another solid finish in New Hampshire. But in the debate just ahead of that primary, Christie hit Rubio hard, most notably when he homed in on a moment when Rubio seemed to repeat a canned line multiple times and started calling the Floridian "Robot Rubio." Rubio finished fifth in New Hampshire and never recovered.

--Analysis by Geoffrey Skelley, 538

DeSantis said Haley opposed Florida’s ban on gender-affirming care, saying she thought “it’s fine and the law shouldn’t get involved with it.” She doesn’t think it’s “fine.” In a June interview on “CBS Mornings,” Haley said “the law should stay out of it” but it should be up to parents until the child is 18. In the interview, Haley said children should “make more of a permanent change” after they turn 18.

During the debate, Haley likened her position on gender-affirming care for minors to age requirements for getting a tattoo: “I said that if you have to be 18 to get a tattoo, you should have to be 18 to have anything done to change your gender.” We’ve heard that comparison before. For what it’s worth, two-third of U.S. states allow minors to get tattoos if their parents consent. And medical experts have told us gender-affirming care is in many cases considered medically necessary, while tattoos are cosmetic.

-Analysis by Katie Sanders of PolitiFact

DeSantis went after Haley's conservative record, saying she "caves any time the left comes after her" and claimed she opposed a Florida bill prohibiting gender-affirming medical care for minors.

Haley countered that she actually opposed the Parental Rights in Education Act that limited discussion of sexual orientation and gender identity in some of Florida's K-12 classrooms, dubbed by its critics as the "Don't Say Gay" bill, because it "didn't go far enough."

"It only talked about gender until the third grade, and I said that it shouldn’t be done at all, that that's for parents to talk about, shouldn't be talked about in schools," she said.

She mentioned that the "most conservative grassroots group in the country" -- Americans for Prosperity Action -- endorsed her last week.

DeSantis followed up by continuing to claim that she opposed a Florida bill prohibiting gender-affirming medical care, such as puberty blockers, on minors.

"That is what Nikki Haley opposed. She said the law shouldn't get involved in that," he said. "And I just asked you, if you're somebody that's going to be the president of the United States and you can't stand up against [that], how are you going to be able to stand up for anything?"

At a town hall in February Haley said she did not think the so-called Don't Say Gay bill "goes far enough," Fox News reported.

-ABC News' Meredith Deliso

“Father time is undefeated,” DeSantis told the debate audience twice, raising doubts over Trump’s age, at 77 years old, amid intervening attacks from Christie that he avoided the original question.

“He’s afraid to answer … this is the problem with my three colleagues,” Christie said. “They’re afraid to offend.” DeSantis wouldn’t respond to repeated questions by Christie and the moderators on the former president’s fitness for office.

“I’ll concede you’re fit, Ron,” Christie said. “You’re a new generation.”

- ABC News’ Chris Boccia