That's true, Nathaniel. But maybe Haley is hoping that actively campaigning, and still having a campaign apparatus running, will give her an advantage over the other also-rans.

—Monica Potts, 538

Remember that the primary is ultimately all about the delegates candidates win to vote for them at the RNC in July. In the delegate math tonight, Trump is coming out way ahead. South Carolina awards delegates in two sets: 29 are awarded to the winner of the statewide popular vote (which are all going to Trump tonight) and the remaining 21 are split equally between the remaining 7 congressional districts. According to ABC's delegate projections Trump has already won 38 delegates tonight, with 12 left to assign in 4 more districts. But if Trump is heading for a 30-point margin statewide, it's unlikely Haley will win any of those that remain.

Our delegate benchmarks model had Haley needing all 50 tonight to be on track for the GOP nomination. It is her home state, after all.

—G. Elliott Morris, 538

Am I the only one who uses the term "bet your bippy"??

—Nathaniel Rakich, 538

Right, so why is Haley sticking around if Trump is the presumptive nominee? We've put together a few hypotheses — spite, in case something happens, sticking it to the man etc — but, as ever with politicians, we cannot discount the possibility that she's in it for her. I keep thinking of Beto O'Rourke's "born to run" comments in the 2020 primary. A lot of politicians think this way!

—G. Elliott Morris, 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