Haley took the stage in a bright red dress and in front of a row of American flags just after 10 a.m. from South Carolina, and announced she was suspending her presidential campaign. She began with a retrospective of the start of her campaign, and reiterated her conservative principles, including a low national debt, a small federal government and the need to promote democracy worldwide by standing by America's allies. With that, the final Trump challenger is out of the race, and Trump is the presumptive nominee, a fact Haley acknowledged.

Like most major candidates who ran for the Republican nomination, other than Trump, Haley had previously signed the RNC's pledge to support the eventual nominee, but she's distanced herself from that pledge a bit recently. Haley didn't endorse Trump this morning, but she did congratulate him, while slightly criticizing the way that he's run his campaign. "We must turn away from the darkness of hatred and division," she said. She went on to say that Trump needed to bring people into his cause, saying, "It is now up to Donald Trump to earn the vote of those in our party and beyond it." Haley has noted in previous speeches that she's captured a sizable portion of the vote in some states, even winning Washington, D.C., and Vermont, signaling that some Republican voters are dissatisfied with the former president as a choice for the future.

In the end, as Meredith noted, she made a somewhat rare reference to the historic nature of her campaign. She's the first Republican woman win any state's nominating contest, and she noted that her mother, a first-generation immigrant, had gotten to vote for her for president in South Carolina. She directed her final lines, quoting from the Book of Joshua, to women and girls who had watched her campaign.

—Monica Potts, 538

Back in late January, we wondered if the 2024 Republican presidential primary might be the shortest in modern history. But because Haley continued to contest the race until Super Tuesday, the competitive period of this year's GOP contest ended up falling short of setting any records. Still, it was undoubtedly on the quick side, historically.

The 2024 Republican race lasted 52 days from Iowa through today, during which time all states and the District of Columbia held 25 contests. The March 6 effective end date puts it just behind the record earliest end of a nomination season (March 3 in the 2004 Democratic contest) and the number of state-level elections (19 in the 2000 Democratic race). Nonetheless, going back to the 1976 election cycle, this year's Republican campaign was much shorter than the median number of competitive days (85 days), state-level contests (39) and end date (April 9).

To be clear, measuring the effective end date of a nomination race's competitive period is not always cut and dry, although it was this time around. We based our approach on political scientist Caitlin Jewitt's work on presidential primary competition, which classified a candidate as their party's presumptive nominee either when all viable opponents have dropped out or when they clinch a delegate majority from the results of primaries and caucuses. In Trump's case, Haley was his last viable opponent.

—Geoffrey Skelley, 538

This morning, as Haley was dropping out, Trump sent a message over his social media platform Truth Social reacting to the results:

"Nikki Haley got TROUNCED last night, in record setting fashion, despite the fact that Democrats, for reasons unknown, are allowed to vote in Vermont, and various other Republican Primaries. Much of her money came from Radical Left Democrats, as did many of her voters, almost 50%, according to the polls. At this point, I hope she stays in the "race" and fights it out until the end! I'd like to thank my family, friends, and the Great Republican Party for helping me to produce, by far, the most successful Super Tuesday in HISTORY, and would further like to invite all of the Haley supporters to join the greatest movement in the history of our Nation. BIDEN IS THE ENEMY, HE IS DESTROYING OUR COUNTRY. MAKE AMERICA GREAT AGAIN!!!"

—Nathaniel Rakich, 538

In her short remarks, Haley quoted Margaret Thatcher: "Never just follow the crowd. Always make up your own mind." She used this quote to encourage the likely nominee, Trump, to appeal to the primary voters who he hasn't won over. She also thanked the girls and women who have supported her campaign, as another (subtle?) reminder of her historic run.

—Meredith Conroy, 538 contributor

In several of California's open congressional districts, tonight could be the end of any suspense about who the next representative will be. Or, it could be the start of an eight-month intraparty slog.

That's because California's unique all-party primary system — where the top two primary vote-getters advance to the general election — allows for either a traditional contest between a Democrat and a Republican or a fight between members of the same party in the general election, and it's not always obvious which one you're going to get. That's the case in at least four open-seat races today — three Democratic and one Republican.

In California's 16th District, there are nine Democrats but just two Republicans vying to replace Democratic Rep. Anna Eshoo. While limited polling of the district suggests that former San Jose Mayor Sam Liccardo or Santa Clara Supervisor Joe Simitian, both Democrats, are the front-runners, if one of the two Republicans consolidates most of the GOP vote and the Democratic vote scatters among the many candidates, a Republican could finish in the top two. In the 2022 primary, the Republican candidates didn't meet that threshold, splitting a combined 22 percent of the vote; the four GOP candidates in the state's Senate race won a combined 24 percent in the district. A Republican advancing would ensure that whichever Democrat also finished ahead would win the general election in November, given the district's partisan bent. But if two Democrats finish in the top two, it'll be a real race.

Same goes in the 30th District, where Adam Schiff is leaving to run for Senate. Twelve Democrats and just two Republicans will appear on the ballot there. In the 2022 primary, four GOP House candidates totaled 21 percent, and Senate GOP candidates combined for a smaller 22 percent. Democratic state legislators Anthony Portantino and Laura Friedman, and Democratic former city attorney Mike Feuer are the front-runners for this seat; if two of those three make it to the general election, it will be an expensive and sharp-elbowed race to November, but if one of the Republicans squeezes in, it's basically over.

In the 31st District, where Democrat Grace Napolitano is retiring, six Democrats and two Republicans are running. In 2022, the one Republican running for the seat, Daniel Martinez, advanced to the general by winning 37 percent of the vote in the primary. Former Rep. Gil Cisneros, state Sens. Susan Rubio and Bob Archuleta, former Monrovia Mayor Mary Ann Lutz and attorney Greg Hafif are all running well-funded Democratic campaigns, creating the possibility that Martinez, who is running again, could finish in the top two instead of two Democrats, effectively ending this race tonight.

And in Kevin McCarthy's old seat, the 20th District, it's a similar story with the parties reversed. There, the two Democrats will probably combine for around 30 percent of the primary vote (in 2022, the House candidates combined for 30 percent and the Senate candidates for 32 percent), while six Republicans fight over the remaining 70 percent (a seventh dropped out but remains on the ballot).

—Jacob Rubashkin, Inside Elections