COLUMBIA, S.C. (AP) — Nikki Haley is perhaps the highest-profile Republican in the nation who has refused to fall in line and endorse Donald Trump’s presidential bid.

It’s unclear how long that might last.

Some allies believe she may be forced to endorse him before the November election to avoid permanently alienating the Republican Party base. Some even suspect that Haley will re-emerge on Trump’s short list of vice presidential contenders in the coming months, despite Trump’s recent statement to the contrary.

But if Haley submits to Trump, as so many of his GOP critics have done, she also risks destroying her own coalition of independents, moderates and anti-Trump Republicans, who are still showing up to support her in low-profile primary contests from deep-red Indiana to deep-blue Maryland. On Tuesday, she gets another chance to demonstrate her sustained strength in Kentucky’s presidential primary contest, which comes more than two months after she suspended her campaign.

Haley’s decision on Trump in the coming months will be closely watched not just by her supporters, but by allies of Trump and President Joe Biden. What she decides to do — and whether her coalition follows — could have a profound impact on this year’s general election and her future as a top-tier Republican whose brand appeals to many people outside her party.

“Nikki Haley could be the person that unites us,” said Thalia Floras, a 62-year-old retail manager from Nashua, New Hampshire, who was a lifelong Democrat before casting a ballot for Haley in her state’s January primary.

But Floras also has a warning: “Nikki Haley has a good place with me now. But if she goes with Trump, I’m done.”

Those close to Haley, a 52-year-old former governor and U.N. ambassador, say it’s unclear what she’ll do.

HALEY VOTERS UP FOR GRABS, BUT ONLY BIDEN TRYING

Haley and Trump haven’t spoken in months. That includes the period after she bowed out of the GOP primary campaign in early March, according to a person with direct knowledge of Haley’s private conversations who was not authorized to speak about them publicly.

And while some Republicans who supported Haley will certainly drift back to Trump organically, the Biden campaign is working to win over her supporters, whom they view as true swing voters.

Biden’s team is quietly organizing a Republicans for Biden group, which will eventually include dedicated staff and focus on the hundreds of thousands of Haley voters in each battleground state, according to people familiar with the plans but not authorized to discuss them publicly.

The Democratic president hasn’t kept his intentions a secret.

Biden issued a statement thanking Haley for her courage to challenge Trump just minutes after she bowed out of the primary race in March.

“Donald Trump made it clear he doesn’t want Nikki Haley’s supporters. I want to be clear: There is a place for them in my campaign,” Biden said at the time.

Trump, meanwhile, said in late January that Haley donors would be permanently banned from his “Make America Great Again” camp. While he has refrained from attacking her since she left the race, Trump hasn’t offered public statements of goodwill either as he has for other vanquished rivals like Florida Gov. Ron DeSantis.

As part of Biden’s sustained outreach to Haley’s coalition, his campaign released a digital ad late last month highlighting Trump’s often-personal attacks against Haley, including his primary nickname of her as “birdbrain” and suggestion that “she’s not presidential timber.”

Asked about Trump’s lack of outreach to Haley and her supporters, senior adviser Jason Miller avoided any mention of her and instead cast doubt on the strength of Biden’s coalition of Black Americans, Latinos and young voters.

“The reality is the Republican Party is united behind President Trump while the Democrat Party has shattered to pieces because of Joe Biden’s disastrous policies on issues like inflation and the border,” Miller said.

Few expect Haley to endorse the Democratic president outright. Such a decision would make it difficult, if not impossible, for her to win a future GOP presidential primary if she decides to run again.

Instead, Biden’s allies are hopeful that Haley, among other high-profile Republican Trump critics, may either stay silent or offer an endorsement focusing on the stakes of the election for democracy rather than direct praise for Biden.

If and when Biden’s team does secure high-profile Republican supporters, it’s likely to wait several more weeks to unveil them to help maximize their impact when voters are paying closing attention to the November election.

A PRO-BIDEN REPUBLICAN SPEAKS

Former Georgia Lt. Gov. Geoff Duncan, a Republican who had backed Haley in the GOP primary, formally endorsed Biden earlier in the month. In an interview, he said he made the decision before talking to Biden’s campaign, although Biden personally called to thank him after Duncan announced his decision.

Duncan didn’t rule out playing a prominent role in the Republicans for Biden group or even speaking at the Democratic National Convention this summer, just as former Ohio Gov. John Kasich did four years ago.

Duncan hopes Haley doesn’t ultimately endorse Trump as so many of Trump’s high-profile Republican critics have done.

“I feel like that would be a short-term sugar high to just gain favor inside the Republican Party,” Duncan said of a potential Haley endorsement of Trump. “She has the right to do what she wants to do. Obviously everybody’s playing the political calculus. But at some point, where do we draw the line?”

The list of high-profile Republicans willing to stand up to Trump in 2024 is extraordinarily small.

Even those who described Trump as a dangerous threat to democracy, like New Hampshire Gov. Chris Sununu, have ultimately endorsed him. Sununu, who was among Haley’s top national surrogates during the campaign, declined repeated requests to comment on her political future. And DeSantis, once Trump’s chief primary rival and another early 2028 prospect, now plans to raise money for Trump’s general election campaign.

HALEY STEPS BACK INTO PUBLIC SPOTLIGHT

Haley has only just begun to emerge from a period of post-campaign seclusion, where she took time to reconnect with family, especially her husband, a military serviceman who recently returned from a nearly yearlong tour overseas.

She plans to deliver a speech on foreign policy later this week — her first public address since ending her 2024 campaign — at the Hudson Institute, a Washington-based conservative think tank where she’s agreed to serve as the Walter P. Stern Chair.

And last week, Haley huddled with dozens of donors and allies behind closed doors in South Carolina, where she thanked her coalition, while largely ignoring Trump. She did not encourage attendees to support his campaign.

Simone Levinson, a Haley bundler who attended the private gathering, said there remains an appetite among Republicans for a next-generation figure who can communicate well and build consensus.

“There is a very strong indication that she has struck a chord that is still continuing to resonate with millions of Americans,” said Levinson, who is based in Florida.

HER COALITION SENDS A MESSAGE

Indeed, without any formal organization, advertising or even private encouragement, the Haley voters continue to show up in low-profile presidential primaries, which will run through the end of June even though Trump is the only candidate still in the running.

Haley earned more than 21% of the vote in Maryland’s presidential primary last week. That’s after hitting similar marks the week before in Indiana and Arizona just weeks after leaving the race.

“She’s articulate and intelligent, which are things that Trump isn’t,” said retired school psychologist Kathy Showen, an independent voter from Cross Lanes, West Virginia, who cast a primary ballot for Haley last week.

Meanwhile, in New Hampshire, Floras said she’ll begrudgingly vote for Biden this fall because she can’t stomach Trump. But she’s hopeful that Haley will run again in 2028.

Her feelings might change, however, if Haley gives in and endorses Trump before the fall election.

“It would really disappoint me if she doesn’t stand up to him,” Floras said. “That would do her in.”