To be blunt, there is no practical reason for Haley to stay in the race at this point. She lost New Hampshire and South Carolina, which according to our modeling should be two of her very best states; as a result, she’s probably not going to win a single contest.

It also doesn’t make sense for Haley to stay in just in case the Supreme Court disqualifies Trump from the ballot. If that happens, other candidates like DeSantis will probably just jump back into the race, and they’ll be better aligned with where the Republican Party is these days. In fact, even as we sit here today, I’d honestly give DeSantis better odds than Haley of winning the GOP nomination, even as an inactive candidate.

Basically, there’s only one good reason for Haley to stay in at this point: principle. To give voice to an anti-Trump vision for the Republican Party. To be able to say “I told you so” if Trump loses in the fall. Because she sure isn’t going to be president.

—Nathaniel Rakich, 538

Trump made a comment about how he would hold an election tomorrow if he could. It's true enough that plenty of countries hold elections on a less fixed schedule, but a candidate facing a number of serious charges related to election interference might not want to joke about that. But some of his other remarks, like his joke about how he doesn't mind talking about himself, reminded me of the feel of the 2016 campaign, and his ability to sometimes make voters laugh and feel in on the joke.

—Julia Azari, 538 contributor

More race projections are coming in mere minutes after polls closed at 7 p.m. The Associated Press has already called the race for Trump based on their polling of voters, which showed Trump with a sizable enough lead to make the call. That call was echoed by other news organizations, including the New York Times, Wall Street Journal, and MSNBC. ABC News also projected Trump as the winner right as polls closed.

—Kaleigh Rogers, 538

I tend to agree with you, Geoffrey. Haley is presenting a very different kind of agenda and policy positions than the more MAGA side of the Republican Party. And voters are noticing the difference.

In polling from YouGov/CBS News in February, likely South Carolina GOP primary voters were asked how they thought each candidate’s policies would impact the country if they were to win the presidency. Seventy-three percent said Trump’s policies would make them financially better off, while only 32 percent said the same of Haley. On immigration, 88 percent of voters said that Trump’s policies would make the U.S.-Mexico border more secure, compared to 53 percent who said the same of Haley’s policies.

The contrast is particularly stark on foreign policy: When asked how Haley’s policies would impact U.S. military involvement overseas, 41 percent said she would increase, 44 percent said she would not change and 15 percent said she would decrease military involvement. The reverse was true of what voters expected from Trump: a plurality of 47 percent thought Trump’s policies would decrease U.S. military involvement overseas, while 20 and 33 percent expected his policies to not change or to increase involvement, respectively.

So I’d buy an argument that Haley may be staying in to keep a more hawkish foreign policy position alive in the party, which makes sense, given her history as U.N. Ambassador.

—Mary Radcliffe, 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