I think you're both right, Nathaniel and Kaleigh, that there's no way Haley can win. She might just be staying in to prove a point and rally the non-Trump base to her side, to take a stand she can point to as prescient if Trump loses. But I think the big issue that she and most other Republicans have been dancing around is the four court cases around the country Trump is facing, his age and a range of any number of unexpected things that could happen between now and November. I think Haley might stay in the race in case something like a criminal conviction, a kind of deus ex machina for the primary that changes the story, without her having to really go after and fight Trump. The truth is he has a lot of potential weaknesses as a potential candidate, no matter how slim the potential for him to be actually sent to prison before November is. Maybe she's trying to position herself as the natural alternative should one of those things happen.

—Monica Potts, 538

Look, Haley is going to lose out to Trump for the Republican nomination. That's been apparent really before we even had votes to count, although it was right to see what actual voters would do in the early contests. But if Haley wants to risk what remains of her political career pushing back against Trump and what he means to the party she's dedicated her political life to, we shouldn't rule out that having longer-term practical implications and influence on voters. Acquiescing to Trump has been a pretty regular thing among Republicans since the 2016 election, but carrying a torch for an alternate vision is something Haley may be inclined to do, to hell with the consequences. Granted, the realities of continuing a campaign with less and less money coming in could end this race pretty soon, but we'll just have to see what she decides to do.

—Geoffrey Skelley, 538

To Jacob's point, the "go ahead and underestimate me" phrase is a very clearly gendered one. And Trump's reputation on this issue hasn't gotten as much attention as it did in 2016, but it's not clear that some of the issues have gone away. Plus, Haley may also be highlighting the fact that, as far as she is from being a real contender for the nomination, this is the closest any GOP woman has come.

—Julia Azari, 538 contributor

People forget this, but McMaster was the first statewide elected official to endorse Trump back in 2016. Haley’s appointment to U.N. ambassador cleared the way for him to become governor, a post he still holds today.

—Nathaniel Rakich, 538

I have become a little obsessed tonight about what we should be expecting Trump to hit in this primary a priori. That is, given Trump is assumed to be the eventual party nominee and almost universally liked in the GOP, should he be winning more than 60 percent in South Carolina?

I already gave my case for answering "no" to that question: Strictly speaking Trump is dominating the delegate count and running ahead of his 2016 vote share in most counties with complete counts this primary cycle. And if you consider that Haley gets a home-state advantage in South Carolina tonight, Trump's adjusted vote share is close to 65 or 70 percent; our delegate benchmarks think Trump should have won 68 percent of the vote based on the demographics of the state alone. That's not the highest number, but it's not the lowest right? Would 65 percent be "good" for Trump? 75 percent? 80?

One counterargument to this centers around how the media has covered historical performances by incumbent presidential candidates. Journalist Jill Lawrence points out that in 1992, Patrick Buchanan challenged incumbent President George H.W. Bush for the GOP nomination and won 40 percent in the New Hampshire primary, holding Bush to 58 percent of the vote. That's an almost identical split to the results from tonight. The New York Times journalist Robin Toner wrote up the results with the headline "BUSH JARRED IN FIRST PRIMARY" and said the result "amounted to a roar of anger" from Republican primary voters.

If Trump was a true incumbent, I imagine the news media would use a similar headline to describe tonight's results in South Carolina. Perhaps our expectations for him are too low, or we're too focused on the broader state of play? Haley said in her concession speech tonight that she will stay in the race indefinitely, so I guess we'll get more data on Super Tuesday — only 10 days from now. The primary lives on!

—G. Elliott Morris, 538