Haley is now speaking live from Charleston, South Carolina, and she just announced she is suspending her campaign. There are now no major Republican candidates left running against Trump.

—Nathaniel Rakich, 538

While you were sleeping, ABC News projected Trump as the winner in the last two presidential contests: Alaska and Utah. Trump currently leads in Alaska 88 percent to 12 percent and in Utah 57 percent to 42 percent.

—Nathaniel Rakich, 538

After a full-ish night's sleep, we're back on the live blog as the winners of several House primaries from Super Tuesday remain unknown. However, the big news this morning is that campaign sources are telling ABC News that Haley will suspend her campaign for president after winning just one primary yesterday, making Trump the presumptive Republican nominee. She will deliver remarks at 10 a.m. Eastern, and we'll cover it live right here.

—Nathaniel Rakich, 538

It's just past 2 a.m., and we've got major results in from most of Super Tuesday's wide-ranging slate of primary contests. So far, Trump has won at least 12 of the 15 states holding GOP presidential nominating contests, while Haley has won Vermont — though whether she hits a 50 percent (plus one vote) threshold of victory there will determine the exact number of delegates she takes home.

Either way, with an estimated 943 total delegates to Haley's 86 so far, per ABC News projections, Trump's well on his way to securing the magic delegate majority number of 1,215 — though it will take at least another week. He's so far secured 667 delegates tonight and is likely to hit the 769 mark that Elliott noted earlier would set him up to mathematically clinch the nomination on March 12. Of course, we're all watching to see if Haley drops out sooner.

In other highlights:

- As expected, Republican Lt. Gov. Mark Robinson and Democratic state Attorney General Josh Stein secured their parties' respective nominations, and will go head to head in what's expected to be a close general election contest for governor.

- Rep. Colin Allred locked up the Democratic nomination in Texas's Senate race, and will face off against Sen. Ted Cruz in the general.

- Democratic Rep. Adam Schiff secured not only the top spot in a top-two primary, but also a likely glide path to the nomination, as the second spot on November's ballot went to Republican Steve Garvey instead of a second Democrat.

We're still tracking a dozen-odd downballot races that have yet to be projected, and awaiting presidential primary results in Utah and Alaska, so we'll see you back here tomorrow ... er, later today, with more results and analysis!

—Tia Yang, 538

Super Tuesday has over 40 years of history that are deeply entwined with a bunch of issues in the presidential nomination process. The term "Super Tuesday" was first used in 1980 but was promoted by Democrats in 1988 as a deliberate effort to give an advantage to more moderate candidates. This was a direct reaction to the idea that the party's 1984 nominee, Walter Mondale, had lost to Ronald Reagan because he was too liberal. This strategy didn't really work out, though, and Democrats ended up nominating another northern liberal, Michael Dukakis.

In other words, this early attempt at a Super Tuesday brought some of the disadvantages of a regional primary, reducing the amount of attention on individual states and pressuring states to move their primaries earlier without really strengthening the influence of the region. Another drawback was that, by trying to enhance Southern influence by holding contests early, Super Tuesday also contributed to the "front-loading" problem", or the issue of having too many delegates selected at the beginning of the primary calendar.

Over time, Super Tuesday has taken on other significance as an important turning point in the race. As party politics scholar Caitlin Jewitt noted, in 2016, everyone thought that Sen. Ted Cruz needed to do well on Super Tuesday, which was heavily concentrated in Southern states where he needed to rack up wins — and when that didn't happen, it was a significant blow to his candidacy. For Biden in 2020, Super Tuesday marked the point when the party consolidated behind him. And in 2008, Super Tuesday made it clear that the Democratic nomination was a real race between Hillary Clinton and Barack Obama, as neither one scored a decisive victory.

It's hard to know exactly how this will play out in 2024. Republicans don't have the same ideological history with the big primary day as Democrats do. But the potential for a turning point in the race is there: Because so many delegates are at stake today, unless Haley wins a significant share of them, it may not make sense for her to stay in the race after tonight.

—Julia Azari, 538 contributor