Super Tuesday primaries 2024: Trump and Biden dominate, Haley drops out

538 tracked how Trump and Haley did, plus key U.S. House and Senate races.

March 5 was Super Tuesday — the biggest election day of the year until the one in November! With former President Donald Trump projected to win 14 of the day's 15 GOP presidential nominating contests, former U.N. Ambassador Nikki Haley announced Wednesday morning that she is suspending her campaign.

It was also the first downballot primary day of 2024, with important contests for Senate, House and governor in states like Alabama, California, North Carolina and Texas.

538 reporters, analysts and contributors broke down the election results as they came in with live updates, analysis and commentary. Read our full live blog below.


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Gill wins in Texas’s 26th

ABC News projects that Brandon Gill will be the Republican nominee in Texas's 26th Congressional District. Because this district is solidly red, that means he is extremely likely to be the seat's next representative, succeeding the retiring Michael Burgess. Gill is a proud member of the MAGA wing of the party; he was endorsed by Trump and is also the son-in-law of conservative political commentator Dinesh D'Souza, who made the documentary "2000 Mules," which falsely alleges voter fraud in the 2020 election.

—Nathaniel Rakich, 538


More House projections

Here are a few more projections from our colleagues at the ABC News decision desk:

- In California's 40th District, a swing seat, Republican Rep. Young Kim will face off against Democrat Joe Kerr in November.

- In Alabama's 2nd District, Democrats Shomari Figures and Anthony Daniels will advance to an April 16 runoff, the winner of which will be favored to win this newly drawn seat in November.

- In North Carolina's 6th District, Republicans Addison McDowell and Mark Walker will advance to a May 14 runoff. The winner will be virtually guaranteed to be heading to Congress next year, as this district was recently redrawn to be safely Republican.

- In California's 20th District (Kevin McCarthy's old seat), Republican Vince Fong will be one of the candidates advancing to the November general election. His opponent is still TBD.

—Nathaniel Rakich, 538


Final thought: Are women going to break more records? Too early to know

As my colleagues have already noted, the Republican primary is essentially over. But Haley's Vermont victory is the first time a Republican woman will win a state's presidential primary. (She also won the primary in D.C.) So, check a box for a broken record. But I had my eye on Republican and Democratic women in downballot races tonight, and overall it looks like Republican women without their party's or Trump's endorsement struggled to win in places where they have a good chance of winning in November. An exception is in North Carolina's 1st District, where wealthy business owner Laurie Buckhout is the projected winner. That seat will be tight contest in November. As of writing this, Democratic women are looking to be doing well in safely blue districts, like California's 12th and 29th, and Texas's 32nd. But tonight's results suggests the senators from California will both be men, after decades of female leadership in those seats. I'll continue to watch women's progress in both parties for 538, to identify trends and whether more records will be broken.

Meredith Conroy, 538 contributor


Final thought: Congress is the most interesting fight now

The presidential primaries are, for all intents and purposes, over. That means we can finally shift our focus to the primaries that are going to have the most impact on the outcome in November, in the House and Senate. Tonight we saw the first of those contests, and they did not disappoint. In Alabama, an appropriator, Rep. Jerry Carl, lost to a firebrand colleague, Barry Moore, in a member versus member primary. (Let's see what that does to morale in the GOP conference.) In California, Adam Schiff successfully engineered an uncompetitive general election against Republican Steve Garvey, freeing up tens of millions in small donor dollars for races elsewhere around the country. In North Carolina, a bevy of upcoming runoffs will help determine what shape the next House GOP conference takes. And in Texas, we're going to find out in the 23rd District just how much deviation from party orthodoxy is tolerated, when Tony Gonzales faces the music for his votes on a gun bill (negotiated by the state's own senior GOP senator!). Presidential season may be over, but the fun is just beginning.

—Jacob Rubashkin, Inside Elections


More thoughts on primary polls

It has become somewhat of a theme of our live blogs this primary calendar to note that Trump's challengers are beating their polls. This first looked to be the case in New Hampshire, where polls significantly underestimate support among Republican likely voters for Haley. But the pattern is more robust than one state: In fact Haley has been beating her polls by an average of five points (in vote share) once you account for undecided voters in these surveys. The consistency of this pattern is striking enough to warrant a post on the matter.

As Mary said earlier, polling primaries is hard! That is betrayed by the fact that POTUS primary polls are by far the least accurate type of poll in 538's pollster rating database going back to 1999. But error is different than bias, and when most of the polls are off in the same direction, something has gone awry.

That "something" is likely the difficulty in obtaining opinions of moderate Republicans from samples of "likely Republican primary voters." Remember that fewer than one percent of people called for a poll actually complete the interview. That means the ones that do are statistical "weirdos" (excuse the technical language). Pollsters adjust for this by weighting their samples to known population benchmarks — like the percent of all adults who are white, over 65, have a college education etc. But in primaries, such benchmarks do not actually exist; pollsters are just making educated guesses about them.

My theory is that most of these primary polls pulling samples of voters from voter registration lists are missing moderate crossover partisans and first-time voters. Additionally, we know that people who are highly motivated to participate in polls (the "weirdos") also happen to be the most politically and ideologically extreme Americans. That's a recipe for polling bias in primaries, where weighting to party, past vote and polarized demographic benchmarks does not control for the partisan consequences of overrepresenting politically engaged Americans.

Now, none of this is to say that polling is "broken." It's just hard to precisely sample a population that doesn't really exist. The polls for the 2024 primary still have below-average error, historically speaking, so we shouldn't go throwing out the baby with the bathwater. But this could nevertheless be a sign of pollsters having a hard time reaching moderate "normie" voters. And if that persists, it could have consequences for general election polls too.

—G. Elliott Morris, 538