What 538's new primary polling averages say about 3 key Senate races

We're now aggregating polls of Senate, House and governor primaries.

February 27, 2024, 11:07 AM

Here at 538, we have polling averages that track public opinion in a number of different areas, including presidential job approval, presidential primaries and the favorability of high-profile politicians. These trackers form part of our core mission of using public opinion data to keep our readers up to date with what's happening across the political landscape.

Today, we're excited to announce another entry in our poll-tracking universe: down-ballot primary polling averages. These trackers aggregate publicly available surveys measuring support for candidates seeking the Democratic or Republican nominations in these pivotal statewide and U.S. House elections — or which candidates are doing best in states that don't have party primaries, such as the top-two primary in California. After all, in most cases only the candidates who advance out of primaries actually have a chance of winning the general election and holding office.

To produce these trackers, 538 uses a polling model specifically trained on primary polls from past cycles, in keeping with our approach of using separate algorithms for different types of polling averages. We include candidates in these trackers if they attain at least 3 percent support in at least five polls conducted by at least three different pollsters and have been included in at least eight polls overall. While we won't go further into the weeds here, readers can delve into our detailed methodology page to learn more.

To kick things off, we have sufficient data to produce polling averages for three U.S. Senate primaries. These three races run the gamut: The winner of a highly competitive GOP primary in Ohio will go on to a high-stakes general election that will be pivotal in determining the next Senate majority; West Virginia's GOP primary will effectively decide the state's next senator; and a top-two primary in California will likely determine whether the November general election will feature a race between two Democrats or one Democrat and one Republican.

A three-way Republican primary in battleground Ohio

In Ohio, three-term Democratic Sen. Sherrod Brown is hoping to overcome his state's Republican lean to win reelection, making the Buckeye State one of the most critical seats for majority math this fall. Brown's endangered status has attracted three major Republican contenders vying to take on the incumbent: Secretary of State Frank LaRose, businessman Bernie Moreno and state Sen. Matt Dolan. And as our tracker shows, the GOP primary is shaping up to be a very close and potentially messy race, with LaRose and Moreno garnering around 20 percent in the polls and Dolan in the mid-teens.

PHOTO: 538's average of the Republican Senate primary race in Ohio.
538's average of the Republican Senate primary race in Ohio.
538 photo illustration

With less than a month to go until the March 19 primary, this contest has a huge number of undecided voters who could swing the race in any direction. The candidates present some notable contrasts, too. Moreno is most aligned with former President Donald Trump, who endorsed Moreno in December, while LaRose, the only statewide elected official in the race, also tried to position himself closer to Trump but failed to garner the highly coveted endorsement. Dolan, meanwhile, ran for the state's other Senate seat in 2022 as something of a Trump critic, finishing third in the GOP primary that nominated a Trump-backed contender, now-Sen. J.D. Vance. Considering how the 2022 race played out, Trump's support may give Moreno an edge. But, as our tracker shows, that's still far from certain right now.

Both Dolan and Moreno have tapped into their personal wealth in pursuit of the Senate seat, while LaRose has relied more on outside support. At the end of 2023, Dolan had loaned his campaign $7 million of the $9.1 million he'd raised overall, while Moreno had self-funded $3 million of $7.3 million. LaRose had raised only $1.9 million ($250,000 from his own pocket), but has attracted significant outside spending: A pro-LaRose super PAC has so far spent $3.2 million supporting him and another $700,000 opposing Moreno, according to OpenSecrets. By comparison, the campaign arm of the influential Club for Growth has spent $1.8 million and a pro-Moreno super PAC has spent more than $900,000 mostly opposing LaRose.

A GOP primary will likely pick Manchin's replacement

While the Ohio GOP race looks up for grabs, the Republican primary in West Virginia looks less in doubt. Our tracker finds incumbent Gov. Jim Justice leading Rep. Alex Mooney by about 38 points, 58 percent to 20 percent, making Justice a clear favorite. The eventual Republican nominee had faced the prospect of a potentially competitive matchup against Democratic Sen. Joe Manchin, but Manchin announced in November that he wouldn't seek reelection. As a result, the GOP primary will now almost certainly decide dark-red West Virginia's next senator.

PHOTO: 538's average of the Republican Senate primary race in West Virginia.
538's average of the Republican Senate primary race in West Virginia.
538 photo illustration

Mooney announced his Senate candidacy right after the 2022 midterms, but Justice entered the race with much fanfare in April and immediately overshadowed Mooney. Since taking office in 2017, Justice has ranked as one of the most popular governors in the country, giving him a solid foundation for voter support ahead of the May 14 primary. Justice is the preferred candidate of the National Republican Senatorial Committee, and he has Trump's endorsement, which surely will help him in arguably the Trumpiest state in the country.

Mooney and his allies have tried to paint Justice as insufficiently conservative, citing Justice's former ties to Democrats — he was initially elected as a Democrat in 2016 before switching parties in 2017. These attacks did not notably move the polls before the most recent public polling of this race came out in November — though admittedly we can't rule out an unexpected shift in Mooney's direction since then.

Mooney does have some financial muscle backing his bid. At the end of 2023, he actually had more money in the bank than Justice, $1.8 million to $1.2 million, thanks in part to the $1.1 million Mooney brought over from his House account at the start of the campaign. Mooney also has the Club for Growth's endorsement; the group's campaign arm has spent $2.1 million attacking Justice, while other groups have spent around $600,000 promoting Mooney. Meanwhile, pro-Justice outfits have made outlays of $1.7 million supporting Justice and around $700,000 opposing Mooney.

Angling for second in California's top-two primary

Like in West Virginia, the 2024 California Senate race looks like a certain win for one party in November — a Democrat in this case. But whereas most states use party primaries to determine who is on the general election ballot, California employs a top-two primary in which all candidates run together regardless of party, and the leading two vote-getters advance to face off in November. The big question in the solidly blue state is whether the two candidates who make it out of the March 5 primary will be a Democrat and a Republican, or two Democrats. Looking at our tracker, Democratic Rep. Adam Schiff is polling at 25 percent and seems likely to finish first. But the race for the second spot is very tight between Republican Steve Garvey (18 percent), a former professional baseball player, and Democratic Rep. Katie Porter (17 percent). Democratic Rep. Barbara Lee is also in the mix, but she's polling shy of 10 percent and looks unlikely to advance.

PHOTO: 538's average of the California Senate top-two primary race.
538's average of the California Senate top-two primary race.
538 photo illustration

California's open-seat race quickly attracted a number of Democratic contenders seeking to succeed Democratic Sen. Dianne Feinstein, who announced her retirement in February 2023. Schiff and Porter anticipated Feinstein's departure, announcing before Feinstein publicly stated she was retiring, while Lee officially jumped in right after it. Feinstein then passed away in late September, prompting Democratic Gov. Gavin Newsom to appoint Democratic Sen. Laphonza Butler. Although Butler could have launched a campaign as an incumbent, she announced two weeks after the appointment that she would not run.

Much of the primary contest has centered on Schiff and Porter, both of whom are fundraising powerhouses. As of Feb. 14, Schiff had brought in $29.8 million in net contributions, while Porter had collected $16.7 million, putting them each well ahead of Lee ($4.8 million) and Garvey ($2.1 million). The two leading Democrats also brought over huge sums left over from their House accounts — $21 million for Schiff and $7.4 million for Porter. Overall, Schiff had $13.7 million heading into the final weeks of the campaign, compared to $4.8 million for Porter — another sign of his overall edge in the race.

Schiff has tried to use that money to influence the race for second place by working to boost Garvey's standing to ensure he faces a Republican opponent in November. Schiff has run ads that criticize Garvey for his conservative views and previous support for Trump, but actually aim to raise Garvey's profile among Republican voters. Should Garvey consolidate most Republican support and advance along with Schiff, the general election would almost certainly be a cakewalk for Schiff in deep-blue California. On the other hand, should Schiff advance with Porter or another Democrat, he would have to seriously contest the Democrat-versus-Democrat matchup all the way to November.


As pollsters release more primary surveys in the coming weeks and months, we'll add more trackers to keep tabs on important nomination races around the country. Although the presidential nomination races seem on the verge of completion, down-ballot primaries will stretch all the way into the late summer, leaving plenty more contests to track as the election cycle progresses. At the very least, we'll be publishing all relevant primary polls on 538's polls page, so even for races that lack sufficient data to produce an average, the numbers that do exist will be available there!