South Carolina Rep. Nancy Mace cited her military school education in backing Trump's candidacy.

"25 years ago, this high school dropout became the first woman to graduate from the Citadel, the Military College of South Carolina," she said.

Mace, the daughter of a brigadier general, said Trump will project military strength and "be prepared to take on the challenges of this historic moment," citing what she said was the threat from China.

Mace also told the convention she was a rape survivor and a single mom. "To women tonight who can relate," she said, "you have a friend and a sister in me. And I will fight like hell for you."

Mace has not always been in Trump's corner. Once a vocal critic, Mace had former South Carolina Gov. Nikki Haley's endorsement in 2022 and received financial contributions from PACs linked to top GOP leaders as she faced a primary opponent endorsed by the former president.

Since then, the roles have been reversed: Trump enthusiastically backed Mace after she endorsed him in the state's presidential primary over Haley, and McCarthy has sought revenge for Mace's vote to oust him from the speakership. Mace handedly won her primary.

-ABC's Brittany Shepherd and Chris Boccia

Florida Rep. Brian Mast, a veteran who lost his legs while serving in Afghanistan, criticized what he called the Biden administration's "adherence to left-wing political ideology."

"I'm not here to sugarcoat it. Joe Biden and Kamala Harris have once again weakened our armed forces and through inflation slashed the size of our military budget," he said. "At the same time, they distracted our troops with millions of hours of so-called extremism training and then base promotions on adherence to left-wing political ideology rather than merit."

He claimed the administration would "rather lose a war than use the wrong pronouns."

"Donald Trump knows that our military needs warriors and not woke weaklings lecturing our warriors," he said.

Mast also criticized Biden's handling of the Afghanistan withdrawal.

"With his botched withdrawal from Afghanistan, Biden delivered what President Trump rightly called the most embarrassing day in American history," Mast said.

As the third night gets underway, with a national security and foreign policy theme, new signs are being given to attendees that read, "Mass Deportation Now!"

Trump has pledged to carry out the largest deportation in U.S. history if reelected, targeting millions of immigrants living in the country without legal permission.

First-time convention attendees are sharing their thoughts on the experience so far.

"It's been like a just like a big party," an alternate from Texas, clad in the state delegation's uniform of an American flag shirt and cowboy hat, told ABC News Digital.

"It's just amazing," said another Texas attendee. "It's fantastic and if you're if you're a political goober kind of like I am, it's the best thing since toast and butter."