Nathaniel, I think that another explanation for Haley’s continued presence in the race is less political and more personal. Clearly, the two candidates don’t get along, and never really have. (Remember that the only reason Trump even tapped Haley as ambassador was as a favor to then-Lt. Gov. McMaster.) With the race getting increasingly chippy and personal, I think Haley may be staying in for longer than politically savvy because she knows just how much it gets under Trump’s skin. This is, after all, a politician who sells shirts that say "Go ahead and underestimate me, that’ll be fun."

—Jacob Rubashkin, Inside Elections

It was pretty clear Trump was going to be the nominee after New Hampshire. I think maybe Haley could be forgiven for trying to stay in for a couple more weeks to see if she could move the needle in South Carolina, a state she knows so well. But after it was clear that Trump’s polling lead wasn’t shrinking, she lost any practical justification for staying in the race.

—Nathaniel Rakich, 538

Shortly after quickly being projected the winner, Trump took to the stage and thanked his supporters. He said his victory tonight would be repeated in November, when they'd gather to tell Biden he was fired. Nine months is a long time to wait, he said, and he asked Gov. Henry McMaster, who was on the stage with him, if there was anything he could do to speed it up. "In certain countries, you're allowed to call your election date," he said, and added he would speed it up if he could. Rather than give a long speech himself, though, he shared the stage with McMaster and the states two Senators, Graham and Scott, who both condemned Trump after the Jan. 6 insurrection. Scott was until recently trying to oust Trump as the presumptive nominee, but Trump said he'd done a better job advocating for him than he had for himself. "I'm just very happy he didn’t have that same energy, drive because I probably would have been out of the race a long time ago," Trump said. Scott took to the stage and asked in a country growl, "Is South Carolina Trump country???" fully in campaign mode. The crowd booed Graham, who spoke flatteringly of Trump regardless.

—Monica Potts, 538

Was there any point besides principle in Haley staying in up until tonight? The writing has been on the wall for weeks, and getting trounced in her home state is a humiliation she could have spared herself. This obviously just makes the inevitable even more apparent, but if she didn’t drop out after New Hampshire, what’s a couple more weeks on principle? (Assuming she has enough money to continue campaigning through Super Tuesday, that is.)

—Kaleigh Rogers, 538

The Republican presidential primary started out in territory pretty friendly to Haley. That changes after today, making the South Carolina primary a sort of last chance for the former Palmetto State governor to prove she actually has a path to the 1,215 delegates necessary to secure the GOP nomination. It looks somewhere between unlikely and impossible that she'll be able to pull that off.

It's all about the numbers. According to the polls, Trump leads Haley by about 30 points among likely Republican primary voters. But his delegate lead is what really matters — and it's likely to be even larger. That's because the South Carolina Republican Party awards its delegates on a winner-takes-all basis. About half the delegates will go to the winner of the statewide vote (almost certainly Trump) and the remainder will go to the winner of each of the state's seven congressional districts. With a 30-point statewide victory, Trump would probably win every district resoundingly; in 2016, the largest difference between Trump's statewide margin (10 points) and his margin in the most anti-Trump county (which he lost by 5 points to Marco Rubio) was only 15 points.

This is all disastrous news for Haley, who needs all 50 delegates from the state to be on track to win the Republican nomination. The competition on and after Super Tuesday will be even tougher. According to the math powering 538's delegate benchmarks, Trump is leading Haley by around 57 points in California and 69 in Texas, the states with the largest delegate hauls on Super Tuesday. Those states also allocate delegates on a winner-takes-all basis, as long as a candidate wins at least 50 percent of the vote.

The primary, in other words, is functionally over. But because Trump has not yet clinched a majority of delegates, Haley's campaign technically has a chance of winning. It's just very, very low.

—G. Elliott Morris, 538