Illinois and Ohio primaries 2024: Trump-backed Senate candidate wins Ohio primary

538 tracked key House and Senate races, including a California special election.

Last Updated: March 19, 2024, 5:29 PM EDT

November’s presidential matchup may be set, but Democrats and Republicans still need to decide who will run in hundreds of downballot races (e.g., for Senate and House) this fall. A batch of these contests were decided on Tuesday, March 19.

Tuesday was primary day in Ohio and Illinois, and in the biggest contest of the day, Republicans chose former President Donald Trump's endorsee Bernie Moreno as their candidate in Ohio’s U.S. Senate race. It was a good night for other Trump endorsees too, as Derek Merrin prevailed in the GOP primary for Ohio's 9th Congressional District, while incumbent Mike Bost is leading his challenger in Illinois's 12th District, as of early Wednesday morning. Plus, a special election in California could have immediate implications for House Republicans’ razor-thin majority.

538 reporters and contributors broke down the election results as they came in with live updates, analysis and commentary. Read our full live blog below.

Latest headlines:

Here's how the news is developing.
Geoffrey Skelley Image
Mar 19, 2024, 6:58 PM EDT

Voters in California’s 20th District may decide McCarthy’s successor today

California held its statewide primary for president and downballot races on March 5, but it still gets to join in on the March 19 fun. There’s a special election in the 20th Congressional District to fill the vacancy left by former House Speaker Kevin McCarthy, who resigned his seat at the end of 2023. The solidly red seat is all but guaranteed to elect a Republican, but the main question is whether the special will produce a winner today or necessitate a runoff.

Representative Kevin McCarthy speaks during a news conference at the US Capitol in Washington, D.C., Oct. 9, 2023.
Valerie Plesch/Bloomberg via Getty Images, FILE

That’s because California special elections don’t work exactly like its regular top-two primary elections. Instead, they operate similarly to Louisiana’s jungle primary system. All candidates, regardless of party, run together in a first round — the race happening today — and if one candidate wins a majority, that candidate is elected. But if no candidate wins a majority, a runoff takes place between the top two candidates. Should no one surpass 50 percent today, the two leading contenders will meet on May 21.

In some ways, the March 5 top-two primary served as a dry run for the special because the leading candidates in that race are also on the special election ballot. The favorite is probably Republican state Assemblymember Vince Fong, who led all candidates with 42 percent of the primary vote two weeks ago. Fong is viewed as McCarthy’s hand-picked successor, and he also has Trump’s endorsement. Fellow Republican Tulare County Sheriff Mike Boudreaux narrowly grabbed the second November spot with 24 percent in the primary, so he’s probably the second-most likely candidate to win or advance to a runoff. But in the primary, Boudreaux only ran a little ahead of Democrat Marisa Wood, who won 21 percent, so she could finish ahead of Boudreaux in the special. This is especially true considering that Republican turnout may not be as high today as it was on March 5 because the special won’t coincide with a much-watched GOP presidential primary.

California State Assemblyman Vince Fong speaks during a press conference in Santa Ana, Calif., June 16, 2023.
Jeff Gritchen/Orange County Register via Getty Images

Differences between the set of candidates running in the special and those who ran in the regular primary could also cause consequential shifts in vote share. Four minor Republicans not running in the special won about 5 percent in the primary, while a minor Democrat not running in the special won about 3 percent. Should this support line up more behind the leading contenders in each party, Fong would find himself closer to a majority to win outright, while Wood might overtake Boudreaux for the second spot in a potential runoff. Moreover, voters know how the primary result played out, so that could influence them to consolidate behind the leading candidates. Still, six other lesser candidates are on the special election ballot, so even if they don’t win much of the vote, what share they do take could still help influence the special’s outcome.

—Geoffrey Skelley, 538

Jacob Rubashkin Image
Mar 19, 2024, 6:52 PM EDT

Ohio 6’s special election turns negative

The special election to replace former Rep. Bill Johnson in Ohio’s 6th District has been a relatively low-key affair since the seven-term Republican left office in January. State Sen. Michael Rulli and state Rep. Reggie Stoltzfus are both running in the regularly scheduled primary and the special election primary for the GOP nomination tonight (so is chiropractor Rick Tsai, who has not raised much money and isn’t seen as a contender); the winner will be a shoo-in for both the June 11 special general election and November general election in this safe red district.

Reggie Stoltzfus, Republican candidate for Ohio's 6th district, attends the Columbiana County Lincoln Day Dinner in Salem, Ohio, Mar. 15, 2024.
Bill Clark/CQ-Roll Call via Getty Images

Both candidates are tying themselves closely to Trump, and spent the first month of the race airing positive ads. But Rulli, who is backed by the U.S. Chamber of Commerce, once had a more moderate reputation in the state Senate when he represented a competitive Youngstown-area seat, while Stoltzfus, who has backing from the socially conservative Family Research Council and Gen. Mike Flynn, has consistently been one of the most conservative members of the state House and has pledged to join the House Freedom Caucus if elected.

In the closing weeks, the race has turned on LGBTQ issues, with Stoltzfus airing ads accusing Rulli of “sponsoring legislation to allow boys in girls’ bathrooms” — a reference to Rulli’s cosponsorship of an LGBTQ anti-discrimination bill (he was one of the only Republicans to back the bill). Rather than lean into his record, Rulli’s allies at Defending Main Street (a wing of the Republican Main Street Partnership) are working to fashion the candidate, who once described himself as “really pro-gay rights” into a conservative outsider who “will stop the Left’s war on children” with respect to transgender issues.

Stoltzfus ($492,000) and Rulli ($479,000) have spent around the same amount of money on ads through March 18, per AdImpact data, with the pro-Rulli Defending Main Street PAC chipping in another $80,000.

—Jacob Rubashkin, Inside Elections

Mar 19, 2024, 6:45 PM EDT

Ohioans are unhappy with the state of their state

In a February survey from Fallon Research, 47 percent of registered voters in Ohio said they thought the state was off on the wrong track, while 29 percent said it was going in the right direction. This includes pluralities across the political spectrum, with 50 percent of Democrats, 41 percent of Republicans and 49 percent of unaffiliated voters all agreeing the state was on the wrong track, compared with 21 percent of Democrats, 31 percent of Republicans and 31 percent of unaffiliated voters saying it was headed in the right direction.

—Mary Radcliffe, 538

Voters fill out their Ohio primary election ballots at a polling location in Knox Presbyterian Church in Cincinnati, Ohio, on Mar. 19, 2024.
Carolyn Kaster/AP

Monica Potts Image
Mar 19, 2024, 6:42 PM EDT

The intraparty battles shaping Ohio state House races

In the Ohio House of Representatives, a speaker battle from last year is playing out in the GOP state legislative primaries tonight.

Republicans have veto-proof majorities in both chambers. But when it came time to elect a speaker at the start of the term last year, a moderate Republican, state Rep. Jason Stephens, beat a far-right candidate, Derek Merrin, in a surprising upset thanks to backing from the chamber’s Democrats and 22 Republicans (including Stephens himself). As speaker, Stephens has control over which bills make it to the floor, and Democrats backed him in exchange for support on some of their policy priorities. Meanwhile, the conservative wing of the party censured those 22 members, dubbing them the “Blue 22.”

This year, Merrin himself is term-limited and running in the 9th Congressional District , while the conservatives who backed him for speaker are now backing challengers against half of the pro-Stephens Republicans. National groups have also stepped in to back these challengers, telling the Statehouse News Bureau that they don't want to just elect Republicans; they also want to support a "bold conservative policy agenda." Adding yet another dynamic to the conflict, the current state Senate President Matt Huffman, a conservative who is also term-limited in the Senate, has jumped into the fray and is running unopposed for a state House seat. He has signaled that he wants to be speaker, and donated to the incumbents who backed Merrin in the speaker fight.

The tug-of-war between the far-right and more moderate members of the Republican Party is playing out in states around the country, and, in some cases, among far-right members themselves. Some of the infighting is centered over what happened in 2020 and the false claim that Trump actually won, and could seriously weaken the state parties heading into competitive general election contests in states like Michigan, Arizona and Georgia. In safe-red Ohio, the consequences could be more localized, but the speaker race, for example, will have a major impact on the kinds of bills the state legislature tries to pass next year around divisive issues like abortion or redistricting.

—Monica Potts, 538

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