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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Allred wins the Democratic Senate nomination in Texas

Back to regularly scheduled programming ... Former Tennessee Titans linebacker and current Congressman Colin Allred is projected by ABC News to win the Democratic primary for Senate in Texas.

Allred was the favorite to win the race tonight, but the bigger challenge will be trying to unseat former Canadian and current Senator Ted Cruz this fall. As Dan noted when Cruz locked down his primary earlier tonight, Democrats are hoping that they can finish what Beto O’Rourke started in 2018, when O'Rourke came within spitting distance of flipping Cruz’s Senate seat. If Democrats' are going to flip any Senate seats, this is likely their best shot, and is an important one if they hope to maintain their narrow majority in the upper chamber. So expect to see a lot of eyes and cash on this race in the months to come.

Kaleigh Rogers, 538


Rubio plus Kasich shows the way for Haley in Vermont

As The Washington Post's Lenny Bronner has pointed out, Haley tends to do better in the places where mainstream or moderate Republicans Rubio and Kasich did better in 2016. In Vermont, Trump won the state in 2016, but by just over two percentage points over Kasich. And together, Rubio and Kasich won 49.7 percent of the vote in 2016, meaning that Haley needs to just about equal their joint performance to win the state. So far, she's roughly doing that. Of the 120 towns with nearly all the expected vote in, Haley's share tops Rubio's plus Kasich's in 65 towns while being under it in another 55.

—Dan Hopkins, 538 contributor


No polls for Palmer

Unfortunately, we’ve seen no polling at all this cycle that includes Palmer. So there’s no way to tell how he stacks up against Trump.

—Mary Radcliffe, 538


Is he even real?

Jason Palmer's (currently down) campaign website features a page called PalmerAI, where a deepfaked video of today's Democratic winner in American Samoa can answer any and all questions you might have about him or his campaign. Talk about uncanny valley.

—Irena Li, 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