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."

Outside the convention center, two delegates spoke with ABC News Digital about what they want to hear when J.D. Vance gives his first speech since being tapped as Trump's running mate.

"I don't know him very well," said one delegate from New Jersey. "I mean, we all know that he was maybe not a fan of President Trump's, which makes it even more interesting, right? But I do think he has the same values."

"That's what we will want to hear tonight, that he has our values that he is going to, you know, that he's going to follow through on those values and when he is only the Vice President, but we're looking forward to four years from now," she said.

Another delegate from California said she was more familiar with Vance, having previously read his memoir "Hillbilly Elegy."

"He's young, he's smart and he knows what he's doing. He has a great compelling story, grew up in poverty, made it to the American dream. What could be more better than that?" she said.

-ABC News' Alexandra Hutzler