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.

That's a wrap!

Well, reader, we were determined to keep this live blog going until every Super Tuesday race had been resolved, but even we have our limits. In preparation for next week's primary live blog, we're wrapping this one up. Here's where things stand in all the races we're still tracking:

- With 99 percent of the expected vote reporting in California's 16th District, we're still not sure who will join Democrat Sam Liccardo in the general election. Democrat Evan Low and Democrat Joe Simitian both currently have 17 percent of the vote, and Low is just 63 votes ahead of Simitian.

- With 99 percent of the expected vote reporting in California's 45th District, Republican Rep. Michelle Steel is a safe bet to advance, but it's a close race for second. Democrats Derek Tran and Kim Nguyen-Penaloza are both at 16 percent, with Tran just 256 votes ahead.

- With 98 percent of the expected vote reporting in the Republican primary for North Carolina's 8th District, Mark Harris is at 30.4 percent, just above the 30 percent threshold he needs to avoid a runoff. The AP has gone ahead and called the primary for Harris, but ABC News has not yet reported whether Harris will win outright or be forced into a runoff.

- With 99 percent of the expected vote reporting in the Democratic primary for Texas's 32nd District, Julie Johnson is similarly hovering at 50.4 percent, which would just barely be enough to avoid a runoff. While the AP has called this race for Johnson, ABC News has not yet reported whether a runoff will be needed.

—Nathaniel Rakich, 538

New projections in California's 20th and 31st

We've got answers on two California House races that were still outstanding! In California's 20th District, ABC News reports that Republican Mike Boudreaux will make the general election, where he will face fellow Republican Vince Fong (who was already projected to advance). It's no surprise that no Democrats made the general election here, as this is the reddest seat in California. (It used to be represented by Kevin McCarthy.)

Similarly, in California's 31st District, ABC News reports that Republican Daniel Martinez will advance to the general election, joining Democrat Gil Cisneros (who was already projected to advance). That's good news for Cisneros; since this is a solidly blue seat, he will have no trouble in the general election against Martinez, whereas he would've faced a tougher campaign against a fellow Democrat.

—Nathaniel Rakich, 538

No runoff after all in North Carolina's 6th

Various news organizations (including ABC News) had projected that Republicans Addison McDowell and Mark Walker would advance to a runoff election in North Carolina's 6th District. However, that contest has now been called off. According to Spectrum News's Reuben Jones, Walker is taking a job with Trump's campaign and will not request a runoff after all. (In North Carolina, the second-place finisher has to request a runoff, it doesn't happen automatically.)

This maneuver is probably not a coincidence given that Trump endorsed McDowell in December. Regardless, it means that McDowell will be the GOP nominee here and very likely the district's next congressman, since Trump carried the 6th District by 16 points in 2020.

—Nathaniel Rakich, 538

Some projections in California

The general-election candidates are set in one of this fall's most competitive House races. ABC News reports that in California's 22nd District, Republican Rep. David Valadao and Democrat Rudy Salas are projected to advance to the general election, setting up a rematch of the 2022 race that Valadao won by just 3 points.

In addition, ABC News reports that Democrat Sam Liccardo and Democrat Gil Cisernos are projected to make the general election in California's 16th and 31st districts, respectively. Their general-election opponents, however, are still TBD.

—Nathaniel Rakich, 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