Former U.N. Ambassador Nikki Haley declined to say on Sunday if she would support former President Donald Trump as her party’s nominee if he beats her in the primary.

A Trump administration veteran who remains the last major challenger to her old boss’ pursuit of a third term, Haley trails Trump by double-digit margins in polls. But she’s outlasted her other rivals and is the last, best hope of Republicans who want to move on from their party’s standard bearer for the last eight years.

“Keep in mind, I am running against him for a reason. I'm running against him, because I don't think… he's the right person at the right time. I don't think he should be president,” Haley said on ABC News’ “This Week.” “The last thing on my mind is who I'm going to support. The only thing on my mind is how we're going to win this.”

“If Donald Trump is the nominee of the end for the Republican Party, he will not win,” she added.

She added that she “highly doubts” Trump would offer his endorsement if she wins.

Previously, Haley said she would support him if he was the nominee and raised her hand at a Republican debate last summer when asked if she would back him.

Trump has beat her handily in the primaries they’ve faced off in, though South Carolina’s primary on Saturday will be the first state they will have competed in over a month. Trump leads Haley in South Carolina — where she served two terms as governor — by over 30 percentage points on average, according to polling aggregator FiveThirtyEight. Nationally, polls show him up around 60 percentage points among Republicans.

Haley has increasingly gone on the offensive as the race narrowed to two, slamming Trump for his age, for his criticism of her husband and other veterans and, lately, for his stance that he would abandon NATO allies to Russian aggression if they did not spend enough on national security.

Russian President “Vladimir Putin is not our friend, Vladimir Putin is not cool. This is not someone we want to associate with. This is not someone that we want to be friends with,” Haley said. “So when you hear Donald Trump say, in South Carolina a week ago, that he would encourage Putin to invade our allies if they weren't pulling their weight. That's bone-chilling.”

“All he did in that moment was he sided with a guy that killed his political opponents, he sided with a thug that arrests American journalists and holds them hostage, and he sided with a guy who wanted to make a point to the Russian people: don't challenge me in the next election or this will happen to you too,” the former U.N. ambassador added, referring to the death of Russian opposition leader Alexei Navalny last week.

Haley said she supported the aid package moving its way through Congress that would send billions in aid to Ukraine and Israel for their respective wars, among other foreign policy priorities. Trump opposes the package and House Speaker Mike Johnson, R-La., has repeatedly expressed doubts he would back the legislation that already made its way through the Democratic-controlled Senate with bipartisan support.

This weekend, Ukrainian troops pulled out of a city in eastern Ukraine after months of onslaught from Russian forces. U.S. and Ukrainian officials blamed the retreat in part on dwindling ammunition reserves as the government there awaits aid from the U.S., its biggest military aid sponsor by far. The largest European war since World War II is approaching the end of its second year.

Haley blamed Biden for failing to make the case to the American people that U.S. support of the Ukrainian war effort is important. But she also criticized congressional Republicans, accusing them of “failing” and “lying to the American people” that they must choose between border security and foreign aid.

“Let's remind the American people that Putin said once he takes Ukraine, Poland and the Baltics are next,” Haley said. “If that happens, those are NATO countries that immediately puts America at war. That is what we are trying to avoid. And that's why this aid package is so important. Ukraine's not asking for troops. They're just asking for the equipment and ammunition to win this war.”

But Haley’s reliance on her foreign policy credentials, contrast of her relative youth and appeal of stability in an era of political chaos appears to have failed to sway enough Republicans. She lost Iowa by over 30 points, New Hampshire by 11 points, the U.S. Virgin Islands by nearly 50 points and was beat out by “none of these candidates” in a Nevada primary that Trump wasn’t even competing in.

Now, polling suggests she is on path to lose her home state by a margin in the dozens. And the party has largely consolidated around Trump: more than 140 members of the House, 30 senators, ten governors and scores of state-level officials have endorsed his campaign.

And the former president has moved to reshape the Republican National Committee to better align with his campaign goals, endorsing close allies to replace the departing RNC chair Ronna McDaniel. He’s called for his daughter-in-law Lara Trump to serve in senior leadership.

“It should be a wake up call for Republicans all over this country. I mean, you look at the fact that we saw on his campaign reports that he used $50 million of campaign contributions to pay for his personal court cases,” Haley said of the shakeup, referring to the slew of civil and criminal cases Trump has battled since leaving office. “Then he tried to get the RNC to name him the presumptive nominee. We don't anoint kings in America.”

“Now he's trying to control the RNC by putting his daughter-in-law as the co-chair and putting his campaign manager is the director of operations,” she continued, saying the RNC would become a “piggy bank” for Trump’s legal fees that stretch into the tens of millions.

In the Sunday interview, Haley did not directly reference a New York City civil court decision last week that fined Trump north of $450 million and banned him from doing business in New York for three years. But on Thursday, she remarked on his troubles before the penalty was revealed.

“Donald Trump is in court today. There will be a verdict on another case tomorrow. And he has a trial starting March 25,” Haley wrote on X, formerly Twitter. “Meanwhile, he’s spending millions of campaign donations on legal fees. All of this chaos will only lead to more losses for Republicans up and down the ticket.”

In a post of his own on X, Trump senior advisor Jason Miller responded to Haley’s Sunday interview by accusing her of being “a Democrat” and asking ABC News "This Week" co-anchor Jonathan Karl “how the hell do you interview Nikki Haley and not ask a basic question such as, oh I don’t know, maybe, ‘can you identify a single state where you can win?’”