Haley hammers Trump's comments about her husband, serving overseas, as he mocks her 'dying' campaign

Former South Carolina Gov. Nikki Haley has stepped up her attacks against former President Donald Trump over the last several days, repeatedly labeling her top Republican rival "unhinged" and releasing another $2 million in attack ads against him in her home state as time ticks down for her to catch up to him in the race for the 2024 Republican nomination.

With South Carolina's Feb. 24 primary closing in quickly -- and 15 more states set to vote just 10 days later, on Super Tuesday -- Haley still trails Trump in polling across the country, according to 538.

She has been trying to make up ground with voters in South Carolina, holding 10 campaign stops and multiple fundraisers since Saturday. She has vowed to continue showing momentum at the ballot box, even if she keeps losing.

Trump, for his part, has increasingly looked toward a likely general election rematch against President Joe Biden and is taking some of the major steps usually reserved for being the party leader -- rather than a candidate still running in the primary.

On Monday, Trump officially endorsed former North Carolina GOP Chair Mark Whatley and his daughter-in-law Lara Trump to replace current Republican National Committee Ronna McDaniel as co-chairs despite the party saying that no changes will be made until after the South Carolina primary.

Trump also backed naming one of his senior advisers, Chris LaCivita, to serve as the party's chief operating officer.

The push to change party leadership has prompted outrage from Haley and her campaign, who blasted it as a ploy to consolidate power and try to control the primary process.

During an appearance on "The Hugh Hewitt Show" on Tuesday, Haley said the potential shake-up should raise "red flags."

"This is not OK when someone now goes and takes over a party so that they can control what happens from here all the way until the convention," she told Hewitt.

"You can only overlook so many things before you start to see something's very wrong," she added.

An RNC spokesperson said after Trump endorsed new leadership that "Chairwoman McDaniel has been on the road helping elect Republicans up and down the ballot and she will continue working hard to beat Biden this fall. Nothing has changed, and there will be no decision or announcement about future plans until after South Carolina."

Haley's increasingly pointed rhetoric comes in the wake of Trump's controversial remarks on Saturday at a rally in Conway, South Carolina, where he said he would "encourage" Russia "to do whatever the hell they want" to NATO allies that he feels don't contribute enough in defense funds.

Trump also falsely suggested that NATO contributions come in the form of loans. In 2006, NATO leaders agreed that member countries (now 31 total) would commit a minimum of 2% of their gross domestic product that would go toward military readiness.

During the same event on Saturday, Trump swiped at Haley's husband, Michael, a major currently deployed to Africa with the Army National Guard.

"He goes to Conway, and he says a few things in his rally that show what happens to him when he's not on a teleprompter. He's completely unhinged," Haley told attendees at an event on Tuesday.

After initially questioning why Haley's husband was not on the campaign trail, Trump took to social media on Monday to say that he should return from his deployment to "come back home to help save her [Haley's] dying campaign."

Haley's campaign has returned fire via a barrage of media appearances, news releases and two new advertisements.

One of the ads, which the campaign is running digitally, focuses on Trump's past comments disparaging the late Republican Sen. John McCain, who served in the Navy and spent several years as a prisoner of war in Vietnam.

Trump called him "not a war hero."

The second ad, announced by the Haley campaign on Tuesday and set to run on TV, accuses Trump of welcoming a "Russian victory" in Ukraine "that will bring more war," echoing Haley's language to CBS News on Monday that she worries about another Trump presidency and the consequences.

"You're going to mock my husband, who's deployed 8,000 miles away? What does that say about someone who wants to be commander-in-chief?" she said. "Because as a military spouse, it makes me worry about Michael's safety. As someone who was in national security, it makes me worry about the future for our kids with him starting a war."

Trump's team has defended his comments about NATO and he has previously said he could end the war sparked by Russia's invasion of Ukraine within 24 hours.

"President Trump got our allies to increase their NATO spending by demanding they pay up, but Joe Biden went back to letting them take advantage of the American taxpayer," a campaign spokesman said in a statement earlier this week. "When you don't pay your defense spending you can't be surprised that you get more war."

Haley has begun to let loose against Trump after months of a more reigned-in message that largely avoided confronting him directly.

On Tuesday, her campaign released a letter from 42 veterans condemning Trump's recent remarks.

"As veterans from all walks of life, we know nothing is more important than having your fellow soldier's back. You do not have our backs," the letter read.

For her part, Haley has billed Trump's comments as an affront to all American service members, saying they make him "not qualified" to be commander in chief.

"You mock one, you mock all. These are men and women willing to shed blood for us to have the freedoms that we hold dear," Haley said on the campaign trail Monday in Elgin, South Carolina. "But this wasn't a slip of the tongue for Trump. When he goes off his teleprompter, that's him speaking from the heart."

ABC News' Gabriella Abdul-Hakim, Hannah Demissie, Lalee Ibssa, Isabella Murray and Soo Rin Kim contributed to this report.