Haley is the last one standing among major candidates competing with Trump for the Republican presidential nomination. With the odds so devastatingly stacked against her, what exactly is Haley trying to do by continuing her campaign and risking getting trounced in her home state?

As I wrote on the site last week, there are certain benefits to presidential runs even when it seems clear a candidate isn't going to become the nominee. One such benefit is raising a candidate's profile in the public eye, something Haley has definitely reaped throughout the primary. When she officially launched her campaign last February, the share of Americans who had either a favorable or unfavorable opinion on her (a decent proxy for a candidate's name recognition) hovered around 55-60 percent. Lately, that number is closer to 75 percent:

It could be that Haley is continuing her campaign to tee up a 2028 bid. The GOP tends to favor also-rans when choosing a nominee in years when there isn't an incumbent running: From 1980 through 2020, there was only one year (2000) when the Republican nominee wasn't either an incumbent or someone who had run previously (if you count Trump's third-party run for president in 2000). And as Trump's only major challenger still in the race, she's still pulling in media and public attention, as well as a decent supply of donations.

Haley has become increasingly critical of Trump. Despite previously serving in his administration, Haley says Trump is no longer "the right president." She's dragged him for his legal woes and drawn attention to his age. Positioning herself in this way could serve future political ambitions by setting her up as the new face of the Reagan wing of the GOP.

Some of the other benefits of a continued run are less likely to explain Haley's tenacity. Given her conservative record as governor, she's not exactly trying to push Trump or the party to the center (despite garnering some support among moderate and independent voters). And given Trump's hardline on loyalty, it's unlikely she'd be able to parlay this campaign into another job in a second Trump administration. Besides, she says she's not interested anyway, telling the “Today” show recently: "I don't want anything. I don't want [to be] vice president."

And of course, we shouldn't write off the potential that Haley still thinks there's a path for her to win. Trump's continued legal disputes remain an unknown factor, and Haley could be hoping that by simply hanging on long enough, she could become the next best option should Trump, for one reason or another, no longer be a viable nominee.

—Kaleigh Rogers, 538

The polls are now closed in South Carolina, and based on an analysis of the exit polls, ABC News is projecting that Trump has won the state’s Republican primary. We’ll be sticking around for a while yet, though, to see what the exact margin is, how many delegates Trump will win and whether Haley will drop out following this decisive defeat.

—Nathaniel Rakich, 538

Haley’s nearly 30-point deficit in her home state isn’t for lack of trying — especially when it comes to advertising. As was the case in New Hampshire, Haley and her allies have outspent Trump, and the 13-to-1 disparity is only more striking when juxtaposed with her lack of movement in the polls.

Haley’s campaign has spent $5.8 million on ads in South Carolina, according to AdImpact, which tracks political ad spending. And her allies at Stand for America, the super PAC set up to support her bid, and Americans for Prosperity Action, the Charles Koch-affiliated group that endorsed her last year, have chipped in a combined $10.3 million. The vast majority of that spending ($14.2 million of it) has come in the last six weeks, since the Iowa caucuses. Another anti-Trump group, the Club for Growth PAC Win it Back, spent $1.7 million against the former president last summer.

Trump, meanwhile, has spent just $1.2 million to date — and his allies’ super PACs have barely spent anything. To put that in perspective, Never Back Down, the super PAC formed to support the failed campaign of Florida Gov. Ron DeSantis, has spent three times as much in South Carolina as Trump has — and it hasn’t aired any ads since July of last year.

It’s not a complete surprise that Haley is pouring so much more money into South Carolina. It’s pretty close to a must-win for her at this point, so she’s not well-served by saving her cash for later. But also, as her most recent FEC filings demonstrated, she actually raised more money than Trump in January.

Will that translate into electoral success? The polling says it’s not likely. But if Haley does pull off the upset of the cycle, her massive spending advantage will be a big part of why.

—Jacob Rubashkin, Inside Elections

Back in 2016, won the South Carolina primary by 10 points, garnering 32 percent of the vote. His two main rivals, Florida Sen. Marco Rubio and Texas Sen. Ted Cruz, each received about 22 percent, with Rubio finishing second. Yet with a crowded field — three other candidates won between 7 and 8 percent — Trump's showing was good enough to carry all but two counties in the state. He also won every congressional district, allowing him to sweep the state's 50 national convention delegates.

Trump's strongest-performing area was in the state's northeast, where he won about 44 percent of the vote in the Myrtle Beach-Florence media market, which made up close to one-eighth of the state's vote. That region should once again be one of Trump's strongest today: A mid-February poll from The Citadel found him winning around two-thirds of the vote in that media market, and a similarly-timed Suffolk University/USA Today survey found him garnering about 7 in 10 voters in the Pee Dee region, which overlaps much of the same turf. He's also poised to improve in a critical area of (relative) weakness in 2016: the vote-rich Upstate area around Greenville in the state's northwest, which contributed about one-third of the 2016 primary vote and was Cruz's strongest region. Both The Citadel and Suffolk polls found Trump at around 70 percent support there. His strength in the Upstate region — the most evangelical-rich part of the state — will come in part from having won over very conservative and white evangelical voters more likely to have backed Cruz in 2016.

For her part, Haley will likely do best in Rubio's strongest places, like the more affluent and well-educated Charleston area, where Haley pulled in between 40 and 50 percent of respondents in surveys from The Citadel and Suffolk. Charleston County proper was one of just two counties that Rubio carried in 2016, the other being Richland County (home to Columbia, the state capital) in the center of the state. Haley could be competitive there, too, as the Suffolk poll found her running within a dozen points of Trump in central South Carolina. Overall, the Charleston and Columbia media markets made up about one-sixth and one-fifth of the state's 2016 GOP primary vote, respectively.

—Geoffrey Skelley, 538

If you are looking for something to listen to while we wait for polls to close and results to come in, allow me to suggest our latest episode of the 538 Politics podcast. We talk about what to expect tonight, including how South Carolina's primary electorate is different from that of other early states and how the results might shape what Haley does next. We also had a debate about a recent poll on presidential greatness and looked at polling that suggests the wars in Ukraine and Gaza have created some significant divides within the two parties.

—Galen Druke, 538