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

In polling conducted since the New Hampshire primary, Trump is viewed favorably by an average of 73 percent of likely South Carolina Republican primary voters, while Haley's average favorability is 51 percent. These numbers are slightly better for the former South Carolina governor than national polling, which, according to 538's tracking, shows 43 percent of Republicans have a favorable opinion of Haley and 81 percent have a favorable opinion of Trump.

—Mary Radcliffe, 538

Spoiler: Whoever wins the Republican primary is probably going to win the state in the general election. Trump beat Biden there by 12 points in 2020, and South Carolina has voted almost exclusively for Republicans in presidential elections since Civil Rights legislation under President Lyndon Johnson flipped most of the South from blue to red. The one exception? The state voted for the Democratic governor of neighboring Georgia, Jimmy Carter, in 1976.

The state reliably votes conservative in other elections too. Its governor, both senators, and six of its seven representatives are Republicans. And many Republican voters there seem fiercely loyal to the former president. Former Rep. Tom Rice, one of ten Republicans who voted to impeach Trump in the House after Jan. 6, was ousted in his midterm primary in 2022.

That said, South Carolina may be changing. Last year it was the fastest-growing state in the country by population growth, driven by the state's growing economy and its relatively affordable cost-of-living. In fact, nearly [10 percent of the potential voting population])) moved to the state since Haley left the governorship in 2017.

While many of those newcomers may have come from the more expensive coasts along the Northeast corridor and California, they don't necessarily seem to be changing the state's GOP electorate, as Haley has struggled to overcome Trump's popularity and name recognition among Republican-leaning new residents. Newcomers or no, Haley's challenges winning over voters in her home state seem not so different from her efforts in the rest of the country.

—Monica Potts, 538

It's not a huge surprise that Haley thinks she can win tonight despite the odds. Her first political success was in a 2004 South Carolina state House Republican primary, in which she unseated a powerful 30-year incumbent to win. She tells that story on the stump, and the message is clear: She's won as an underdog before.

As a legislator, Haley carved out a reputation in South Carolina as an outsider taking on state power. She sponsored a bill to force roll call votes on issues like raising legislator pay, losing support from her colleagues and a race for a committee chair position in the process. Later, as governor, she became known for luring businesses to the state, siding with business over labor, signing a 20-week abortion ban and blocking Medicaid expansion.

On social issues, though, she has tried to walk a middle path. Haley has talked about the racism her Indian American family faced in rural South Carolina, and supporters have said the "good ol' boys" network never quite accepted her in state politics. But she also frames her success as an example of how the South has made progress. She didn't tackle the issue of the Confederate battle flag flying over the State House until after a racist shooting in Charleston in 2015, in which nine churchgoers were killed in Emanuel AME Church. She has also sidestepped more recent controversies, like anti-transgender bathroom laws.

Of course, all of her history in the state hasn't seemed to help her against Trump. In polls, she's winning only about a third of potential voters. She may be used to playing the role of David, but not all Goliaths fall in defeat.

—Monica Potts, 538