Voting in South Carolina's all-important Republican presidential primary ends today

Former U.N. Ambassador Nikki Haley faces a critical election today in her bid for the GOP presidential nomination in her home state of South Carolina.

Haley, who was elected twice as governor in the state, has yet to win a presidential contest. In South Carolina, most polling has shown her lagging significantly behind former President Donald Trump — who has far and away been the party's front-runner throughout this entire race.

Despite that, Haley's campaign has banked a lot of time and resources in South Carolina. Her campaign raised millions last month – and has received influxes of cash from a billionaire donor, in particular.

On Tuesday, she vowed to stay in the race even if she doesn't win the South Carolina primary.

"South Carolina will vote on Saturday, but on Sunday I'll still be running for president," Haley said during a campaign speech in Greenville, S.C. "I'm not going anywhere."

She also pledged that she would continue campaigning until "the last person votes." She later told NPR she would stay in though at least Super Tuesday, which is on March 5.

"I haven't actually sat down and thought about what comes after that," Haley said. "But our goal was between South Carolina and Super Tuesday, another 20 states have voted, and that's more of the representation we want, let people's voices be heard."

On Friday, her campaign announced they were launching a "seven-figure" national ad buy ahead of Super Tuesday.

Trump has mocked Haley for staying in the race. During a town hall event hosted by Fox News in Greenville, S.C., on Tuesday, Trump said, "I don't think she knows how to get out" of the race.

"I really don't," he said. "She just can't get herself to get out."

Polls in South Carolina close at 7 p.m. E.T.

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