With results coming in from Virginia, I'm keeping an eye on the Commonwealth's southeastern corner. Not only is it home to Virginia Beach, the largest city in Virginia, it's also home to a substantial number of military families. In 2020 at least, donations from those serving in the U.S. military split more evenly between Democrats and Republicans than some might expect. So far, Trump is winning Virginia Beach by roughly a 2 to 1 margin, while Haley is keeping it closer in neighboring Norfolk with 42 percent of the vote so far.

—Dan Hopkins, 538 contributor

ABC News projects that Trump will win the GOP primary in Maine. With about 8 percent of the expected vote counted, he leads Haley, 69 percent to 22 percent.

—Jacob Rubashkin, Inside Elections

Folks who are reading a 538 live blog have probably seen the general election polling showing Trump leading nationally by 2-3 percentage points and leading in the battleground state by more like 3-5 points. That is the answer you are looking for if you want to understand the current state of the races. Emphasis on current, meaning 8 months before the actual election when polls are historically not predictive. Now, there may be caveats about polls shifting less than usual over the coming months because Trump and Biden are already so well defined. But that's a theory, not a fact.

One dynamic in the primary that I do think is worth thinking about in understanding whether those numbers will shift or how, is where the challenge is coming from in both parties. Trump is being challenged by someone who is ideologically closer to Biden than to his Right flank. Biden's most enthusiastic opposition is coming from his left flank, aka not ideologically anywhere close to Trump. Folks always have the option of staying home or voting third party, but if I was Trump's campaign I would not like that dynamic ... particularly given that Biden's victory in 2020 came from an overperformance among independent/moderate voters.

Look at me, doing the thing I just said we shouldn't do.

—Galen Druke, 538

With 28 percent of the expected vote reported, the Republican presidential primary in Vermont looks so close. Right now, Trump and Haley are tied with 48 percent.

—Monica Potts, 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