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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ABC News projects Biden and Trump will win in Arkansas

Based on an analysis of the vote, ABC News projects that Trump and Biden will win their presidential primaries in Arkansas. With about 7 percent of the expected vote in, Womack is holding onto his lead in the 3rd Congressional District 60 percent to 40 percent against Penzo.

—Monica Potts, 538


Answer: Democrats!

I'll be very interested to see, when the dust settles tonight, if the polls are more on the money in states with closed primaries, where bored (or wily) Democrats can't vote in the Republican Party primary for Haley. A lot of the exit polling data we've seen on Haley supporters and who they'll vote for in the general election, or whether they approve of Biden's job performance, makes me wonder how many of her voters are just plain old Democrats who are getting screened out of a lot of GOP primary polling. But we'd see a difference in closed primary states (to the extent we have robust polling there to make the comparison)!

—Jacob Rubashkin, Inside Elections


Answer: Polls might be struggling to pick up some more Democratic-leaning voters

Julia, I'm suspicious that the reason Trump's lead in primary polling has been somewhat exaggerated is that pollsters are not necessarily capturing some of the independents who are showing up to vote in a GOP primary. As Nate Cohn recently pointed out in The New York Times, some pollsters have filtered for likely GOP primary voters by mostly or only looking at voters who've voted in Republican primaries. But a fair number of independents, including Democratic-leaning ones, wouldn't necessarily fall in that category. But with Biden a lock to win the Democratic nomination — barring something happening outside of the voting booth — Democratic-leaning voters have only one race to get involved in. Although we know there aren't that many "cross-over" voters who participate in the opposing party's primary, some high-propensity Democratic voters and some Democratic-leaning independents have probably voted in states that allow non-Republicans to cast ballots in the GOP primary.

—Geoffrey Skelley, 538


Answer: The 'silent voters' aren't so silent, anymore

In 2016, people who said they were undecided in polls were more likely to vote for Trump as "professor polls" explains in this great 538 video I show my students. But in 2024, Trump supporters aren't so shy. It's the rest of the GOP that might be more bashful.

—Meredith Conroy, 538 contributor


Polling is hard. Like, really hard.

I just want to underscore Elliott's point about how hard polling has gotten with a quick story I wrote up in a paper with Tori Gorton called "On the Internet, No One Knows You're An Activist." We were trying to survey lower-engagement voters, so we drew a sample of 9,937 registered Pennsylvania voters who hadn't consistently voted 2012-2018. Then, we matched them to Facebook accounts and served ads to 1,321 inviting them to take a survey. 66 people clicked on our ad, 7 began the survey, 6 completed it, and 1 person left an email for follow-up. I of course want to express my deep gratitude to that one respondent. But beyond that, a 0.4% response rate magnifies sampling errors, because very small differences in people's willingness to take polls can add up to very large errors in vote margins. That's especially true in primaries, where pollsters can't use partisan identification to stabilize the results.

—Dan Hopkins, 538 contributor