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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Moore wins Alabama's 1st District Republican primary

ABC News projects that Rep. Barry Moore will defeat fellow Rep. Jerry Carl in Alabama's 1st District GOP primary, winning the lone incumbent-versus-incumbent primary we're expecting to have this cycle.

—Geoffrey Skelley, 538


One last look at North Carolina

The big races I was eyeing in North Carolina are tightening up. In the 1st District (which is set to be the only competitive Congressional race in the Tar Heel state in November), wealthy businesswoman Laurie Buckhout is projected to win the GOP nomination. The 6th District looks destined for a runoff. In the 8th District, Mark Harris (whose 2018 win was thrown out due to allegations of ballot fraud) is projected to win the Republican nomination. And in the 13th District, Kelly Daughtry, an attorney who came in third in the Republican primary in 2022, is creeping closer to the 30 percent threshold needed to avoid a runoff. Not a ton of surprises, but an interesting night downballot for sure!

—Kaleigh Rogers, 538


What's going on in Katie Porter's district?

The race in California's 47th District is competitive within the Democratic field where, as we've mentioned, Rep. Katie Porter decided to run for Senate, opening up her House seat. The House primary she won in 2018 to face (and eventually defeat) the Republican incumbent, Mimi Walters was also competitive. In fact, Dave Min, who is running today, was the favored Democrat in that 2018 primary, but Porter beat him out to finish second, behind Walters, and went on to win the seat. With 46 percent of the expected vote in, Min is leading his closet rival, Joanna Weiss, by about 8 points.

Meredith Conroy, 538 contributor


A political scion advances in Alabama's 2nd District Democratic primary

Redistricting made Alabama's 2nd District Democratic-leaning, and a bevy of candidates jumped into the party primary with a shot at winnable seat. But in Alabama, primary winners must win a majority, so the crowded race has made an April runoff likely. With about 80 percent of the expected vote reporting, former Justice Department official Shomari Figures leads with nearly 44 percent. ABC News has projected that Figures, the son of longtime state Sen. Vivian Figures and the late state Sen. Michael Figures, will advance to the likely runoff. The race of the second runoff spot is not set, but state House Minority Leader Anthony Daniels has 22 percent, ahead of state Rep. Napoleon Bracy's 16 percent. Daniel actually hails from Huntsville in the north of the state, far from the southern Alabama base of the district. Bracy is from Mobile, and there are still some votes left to report from there, so he can't be discounted.

—Geoffrey Skelley, 538


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