Former U.N. Ambassador Nikki Haley suspended her presidential campaign Wednesday, leaving former President Donald Trump as the only major Republican candidate still in the race.

Her decision came one day after Super Tuesday, when she scored an upset win over Trump in Vermont and denied him a 50-state sweep but failed to win any other states. She also won the Washington, D.C., primary last weekend.

“I am filled with gratitude for the outpouring of support we've received from all across our great country, but the time has now come to suspend my campaign,” Haley said during a brief speech in Charleston, South Carolina. 

“I said I wanted Americans to have their voices heard. I have done that. I have no regrets. And although I will no longer be a candidate, I will not stop using my voice for the things I believe in.”

She did not endorse Trump. 

“I have always been a conservative Republican and always supported the Republican nominee,” Haley said. “But on this question, as she did on so many others, [former British Prime Minister] Margaret Thatcher provided some good advice when she said, ‘Never just follow the crowd. Always make up your own mind.’”

Haley instead called on Trump “to earn the votes of those in our party and beyond it who did not support him,” adding, “I hope he does that.”

Haley had previously pledged to the Republican National Committee she would support the party’s eventual nominee. But in an interview with NBC News’ “Meet the Press” on Sunday, she said she is no longer bound by that promise and would “make what decision I want to make.”

The former South Carolina governor took a few parting shots Wednesday at both Democrats and Republicans. She said a smaller government is needed because “our national debt will eventually crush our economy.” She called Congress “dysfunctional” because “it is filled with followers, not leaders.” And she said if the United States does not stand by its allies in Ukraine, Israel and Taiwan, “there will be more war, not less.”

Haley staged a successful campaign in the sense that she outlasted more than 10 other Republican candidates, a field that included Florida Gov. Ron DeSantis, former Vice President Mike Pence and Sen. Tim Scott of South Carolina. But despite picking up some key endorsements and raising substantial sums of cash, she never broke through against Trump in the primaries.

Heading into Super Tuesday, Haley had won only the D.C. primary. She failed to beat Trump in New Hampshire, thought to be a friendlier arena because of its large contingent of independents and the ability for Democrats to vote in the GOP primary. She then won just three of 50 delegates in her home state of South Carolina. 

And Haley suffered an embarrassing defeat in a Nevada primary that did not include Trump. (Trump competed in the state’s caucuses instead. “None of these candidates” was the top vote-getter in the primary.)

She eked out a win in Vermont on Tuesday, taking nearly 50% of the vote to Trump's nearly 46% but failed to win other states where she appeared best poised to compete, including Maine and Virginia, and was defeated soundly by the former president in states such as Texas.

Haley defied calls for weeks to step aside, saying she believed more voters deserved to have a choice other than Trump. Haley also has argued that she, not Trump, had the best shot at beating President Joe Biden in the general election. 

In a message he posted on Truth Social as Haley was speaking Wednesday, Trump gloated that Haley “got TROUNCED last night, in record setting fashion” and said he hoped she stayed in the race.

In a statement Wednesday morning, Biden commended Haley for her “courage” in taking on Trump.

“It takes a lot of courage to run for President – that’s especially true in today’s Republican Party, where so few dare to speak the truth about Donald Trump,” he said. “Nikki Haley was willing to speak the truth about Trump: about the chaos that always follows him, about his inability to see right from wrong, about his cowering before Vladimir Putin.

“Donald Trump made it clear he doesn’t want Nikki Haley’s supporters,” the president added. “I want to be clear: There is a place for them in my campaign. I know there is a lot we won’t agree on. But on the fundamental issues of preserving American democracy, on standing up for the rule of law, on treating each other with decency and dignity and respect, on preserving NATO and standing up to America’s adversaries, I hope and believe we can find common ground.”

After becoming the lone major challenger to Trump, Haley sharpened her attacks against him. She criticized the former president for vowing retribution against his political enemies if elected, for saying he’d encourage Russia to attack NATO countries that did meet their financial obligations to the alliance, for adding trillions to the national debt as president and for helping kill a bipartisan agreement on border and immigration reform.

Trump, meanwhile, tried to brand Haley as a moderate and repeatedly insulted her intelligence by calling her “Birdbrain.” At one point, he even seemed to suggest that Haley’s husband, a member of the South Carolina Army National Guard, deployed to Africa to get away from her. 

Haley attacked both Trump and Biden on one key factor: their ages, calling for mental competency tests for politicians over age 75 and advocating for term limits.

Her campaign was still a historic one: Not only did she deny Trump a victory in Vermont, but also became the first woman ever to win a GOP state primary. Over the weekend, she became the first woman to win any Republican primary when she finished first in the District of Columbia.

Haley was also a fundraising juggernaut, raising $12 million in February in addition to heaps of money in the months prior.

But with her decision on Wednesday, the election is all but formally set to be a 2020 rematch between Trump and Biden, a prospect that, per polling, very few Americans are excited for.