Texas Republican Rep. Dan Crenshaw has long had a bit of a fractious relationship with the more extreme members of his party. He was one of just a few Republicans to vote to certify Biden's election in 2020, and he's often feuded with fellow Republican, Georgia's Marjorie Taylor Greene. Though he's been a reliable vote against the Biden agenda and is backing Trump again, co-hosting a fundraiser for the former president, he's clearly not alright with the base.

With about 73 percent of the vote reporting, he leads his conservative challenger Jameson Ellis by just 17 points. That might seem like a lot, but consider that just two years ago, Crenshaw also faced Ellis in the 2022 GOP primary and defeated him by a much wider 58-point margin.

—Jacob Rubashkin, Inside Elections

Democratic Rep. Sheila Jackson Lee is projected to win the Democratic primary in Texas's 18th District, fending off a challenge from former Houston City Councilwoman Amanda Edwards. Jackson Lee lost a bit of steam in her congressional campaign by running for Houston mayor last year, a race she lost. But after jumping back into her reelection bid, she has managed to edge out the young upstart challenger in Edwards, all but guaranteeing her another term in this deep-blue district.

—Kaleigh Rogers, 538

I don't doubt that there are parts of the GOP electorate this cycle that are hard to capture, and they may well be Democratic-leaning independents or just straight up Democrats. But equally importantly, we should keep in mind that primary polls are the most prone to error of all the kinds of election polls out there. And actually, outside of Michigan, the polls have been well within the 8 to 10 percentage points of average primary polling error we should expect.

—Galen Druke, 538

ABC News is projecting that Biden and Trump will win their respective presidential primaries in Texas, as will Republican Sen. Ted Cruz, who Democrats are angling to unseat this fall. The race for the Democratic Senate nomination in Texas is hot, though as I mentioned earlier, the front-runner is Rep. Colin Allred, a former NFL player and civil rights attorney who has represented the Dallas area since 2019.

—Kaleigh Rogers, 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