Ambassador Nikki Haley is ramping up her attacks on President Trump ahead of the South Carolina primary, launching a new ad attacking Mr. Trump for disrespecting veterans, which comes as she criticizes the GOP frontrunner for recent comments about NATO, her husband Michael, and tariffs on Communist Chinese goods.

The new ad from Mrs. Haley’s campaign recounts four instances when Mr. Trump appeared to mock veterans as well as a reference to recent comments the former president made about Mrs. Haley’s husband.

“It’s time to support leaders who support our troops,” the ad reads.

With the South Carolina GOP primary set for February 24, Mrs. Haley is sharpening her criticism of the former president in an effort to make what could be a last stand in the GOP primary in her home state.

The associate editor of Sabato’s Crystal Ball at the University of Virginia Center for Politics, Miles Coleman, tells the Sun that “pulling an upset in S.C. would be necessary but not sufficient for Haley to get the nomination.”

“Ever since New Hampshire voted, my main question hasn’t been whether or not Haley makes it to the convention — it’s been whether or not she drops out before South Carolina,” Mr. Coleman says.

The new ad, released Monday, is a doubling down by Mrs. Haley’s campaign on the strategy of criticizing Mr. Trump for his recent comments about her husband and America’s NATO allies.

At a rally in South Carolina on Saturday, Mr. Trump remarked of Mrs. Haley: “Where’s her husband? Oh, he’s away.” He added: “What happened to her husband? Where is he? He’s gone.” Mr. Trump continued then, adding: “He knew. He knew.”

Mrs. Haley’s husband, Michael Haley, is deployed in Africa with the South Carolina Army National Guard, his second overseas deployment. Mrs. Haley fired back at Mr. Trump Saturday, saying, “If you mock the service of a combat veteran, you don’t deserve a driver’s license, let alone being president of the United States.”

Mrs. Haley has since escalated her attacks on Mr. Trump, who has repeatedly mocked veterans over the years, such as the late senator of Arizona, John McCain, of whom he said in 2015, “I like people who weren’t captured.”

Mr. Trump himself received five draft deferments during Vietnam, the fifth of which was a medical deferment due to Mr. Trump’s claim that he suffered from bone spurs.

Mr. Haley joined his wife in attacking the former president, saying in a tweet: “The difference between humans and animals? Animals would never allow the dumbest ones to lead the pack.”

Since the episode, Mrs. Haley has attacked Mr. Trump for what she says is repeated disrespect of veterans, saying in a new video “I am proud of Michael’s service. Every military spouse knows it’s a family sacrifice.” Mrs. Haley has also sought to make an issue of Mr. Trump’s age.

“I have long talked about the fact that we need to have mental competency tests for anyone over the age of 75,” Mrs. Haley said. “Donald Trump claims he would pass that — maybe he would, maybe he wouldn’t.”

Mrs. Haley has also criticized Mr. Trump for saying he would encourage Russia to “do whatever the hell they want” to NATO countries that don’t pay enough for defense.

Mr. Trump has often been a critic of NATO members who do not meet the alliance’s target of spending 2 percent of the country’s annual GDP on defense.

Mrs. Haley responded to Mr. Trump in an Interview with Bloomberg TV, saying, “It is a mistake for Trump to side with Putin over our allies.”

“Do we want NATO to pay more? Of course we do. But the last thing we’re going to do is side with a thug. Keep in mind, Putin kills his opponents,” Mrs. Haley said.

In the same interview, Mrs. Haley called Mr. Trump’s promise to impose a 60 percent tariff on Chinese imports “ludicrous.”

“That’s going to affect American families on anything from baby strollers to appliances,” Mrs. Haley said. “Every American family will see at least a $2,800 increase in their taxes.”

The most recent dispute between Mrs. Haley and Mr. Trump comes as the rivalry between the two is becoming more bitter ahead of the South Carolina GOP primary, a primary that will likely be Mrs. Haley’s last and best opportunity to gain traction in the GOP primary in any way.

Recent polling in the state, though, shows that the race is Mr. Trump’s to lose, as he leads Mrs. Haley 65 percent to 32 percent in the FiveThirtyEight average of polls.

Mr. Coleman says that if Mrs. Haley stays in until South Carolina, with the way the race is going now, “she’ll almost certainly be ‘Rubio’d’ later this month.”

“In 2016, Trump embarrassed Rubio in Florida and basically forced him out of the race,” Mr. Coleman says. “Just as Rubio was able to win Miami — and lose everything else in Florida — Haley will probably be able to carry some upscale precincts in the orbits of Charleston and Columbia, but that’s not enough for a majority.”