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

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

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.


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How much is a House seat worth?

And Geoff, it only cost Taylor $1.7 million. Not a bad deal given how much some other self-funders have spent just to come up short. (David Trone dropping $13 million to lose my home district, MD-08, in 2016 comes to mind.)

—Jacob Rubashkin, Inside Elections


Senate primary polls usually misfire, but not by this much

As I noted in the opener for our live blog today, the polls in Ohio's Senate race showed a "close race" between Moreno and Dolan, with LaRose in a somewhat distant third. The result, however, is anything but close. With 85 percent of the expected vote reporting, Moreno currently has a lead of 17 points, making for an 18-point miss in our polling average (after you account for some rounding). This is not the largest miss in Senate primary polling history — that honor belongs to surveys of the 2018 Republican primary for a special Senate election in Mississippi — but it is nevertheless very large. An 18-point miss is about 2 times the size of the expected miss of primary polls in historical Senate races (8.2 points).

This miss is notable because it's actually larger than historical expectations. That's the opposite of what we've been seeing with presidential primary polls — which, while they have systematically overestimated support for Trump this cycle, have at least been more accurate than the historical average presidential primary survey. Pollsters will need to do some work to figure out what went wrong.

—G. Elliott Morris, 538


Ohio's 2nd District GOP primary looks to have a winner

In Ohio's 12th District Republican primary, David Taylor is projected to win, according to ABC News. With more than 90 percent of the expected vote reporting, Taylor has 25 percent of the vote, putting just ahead of Tim O’Hara (21 percent) and Larry Kidd (19 percent) in a crowded 11-candidate contest. Considering this is solidly red turf, Taylor is all but certain to be the next representative from this suburban-exurban Cincinnati area seat.

—Geoffrey Skelley, 538


How geography has helped make for a close Illinois's 12th District GOP primary

With 68 percent of the expected vote reporting, Bost leads Bailey 53 percent to 47 percent in the Republican primary in Illinois's 12th District. But Bost looks to be on pace for a potentially narrower win — and perhaps could even lose. After the 2020 Census, Illinois Democrats drew a gerrymander that packed more Republican-leaning turf into Bost's 12th District in southern Illinois, which he had represented since 2015. About half of the new-look version of the seat had been in Bost's old district, but much of the eastern part of the seat was new to him. Meanwhile, Bailey's old state Senate seat made up a large chunk of that eastern section, giving him a geographical base of support for this primary despite facing the incumbent Bost.

As things stand, Bost is winning about 70 percent of the vote so far in the area he represented prior to the 2022 election, while Bailey is winning 73 percent in the counties that were in his old state Senate seat. The two are running about even in the remaining turf. The good news for Bost is that more of the primary vote will likely come from his neck of the woods. But the good news for Bailey is that more outstanding votes are likely left to be counted in his area of the district. A back of the envelope calculation based on each candidate's showing so far would put Bost up about 51 percent to 49 percent by the time all is said and done, but that is too close to call.

—Geoffrey Skelley, 538


Abortion may motivate Ohio Democrats

Cooper, I wonder how much the potential threat of limiting abortion access in Ohio could impact that Supreme Court race. In 2023, voters in the state passed a constitutional amendment protecting abortion access. In a sign that abortion may continue to be an issue that divides Republican-leaning voters, a November Emerson College/WJW-TV/Nexstar survey conducted just after that election asked registered Ohio voters how they voted on the abortion measure and how they plan to vote in November this year.

Twenty-six percent of those who voted to pass the abortion rights measure said they plan to vote for Donald Trump, suggesting that a fair number of Republican or Republican-leaning voters supported it. (In comparison, just 10 percent of those who voted against the measure said they planned to vote for Joe Biden.) Abortion also seemed to drive turnout among Democratic-leaning voters in last November's election: Among those that said they voted on the abortion referendum (either for or against), 41 percent said they'd vote for Biden, while only 28 percent of those who didn't vote supported Biden. (About half of both 2023 voters and nonvoters supported Trump.)

So if the issue of abortion becomes salient in the state Supreme Court race, there could be a close race coming our way in November.

—Mary Radcliffe, 538