Oklahoma held its federal primary elections on June 16, 2026, clearing the field for most November congressional races while sending two contests to an Aug. 25 runoff. The Senate seat is the only statewide federal race on the ballot this cycle.
Oklahoma’s Open Senate Seat Splits Along Party Lines
The seat came open after Markwayne Mullin left Congress to join President Trump’s Cabinet as Secretary of Homeland Security. Republican Kevin Hern, who had represented Oklahoma’s Congressional District 1 since 2019, ran for the open seat and won his party’s nomination decisively.
70% Share of Republican Senate primary votes Hern captured statewide on June 16, 2026, according to Oklahoma Voice.
No Democratic candidate cleared the 50% threshold required under Oklahoma law to avoid a runoff. N’Kiyla Jasmine Thomas led the Democratic field with 45% of the vote, while Jim Priest finished second at nearly 24%. They will face off again on Aug. 25 to determine who challenges Hern in November. With Hern’s near-70% showing, Democrats enter that general election as heavy underdogs in a state Trump carried by wide margins in 2024.
Two Aug. 25 Runoffs Will Fill Out the November Ballot
Hern’s departure from CD-1 created a second crowded race. State Rep. Mark Tedford (R-Tulsa) led the Republican primary with 32%, followed by pastor Jackson Lahmeyer at 26%. Because neither passed 50%, they go to the Aug. 25 Republican runoff. Democrat John Croisant, who had no primary opponent, waits for the winner.
Oklahoma’s four other incumbent Republican House members all secured their nominations without runoffs. Josh Brecheen won CD-2 with 79% and will face Democrat Brandon Wade in November. Frank Lucas won CD-3 with nearly 71% and faces Democrat Suzie Byrd.
Tom Cole won CD-4 with 71% and faces Democrat Mitchell Jacob and independent Rocco Bonacci. Stephanie Bice ran unopposed in CD-5 and will face Democrat Jena Nelson. All four incumbents carried Trump endorsements heading into their primaries.
Over 551,717 Oklahomans cast ballots across both parties in the Senate primary, which was the only statewide federal race on the June 16 ballot. That turnout figure matters because runoff elections typically draw far fewer voters, meaning a smaller, more organized group of Democrats will effectively choose the party’s Senate nominee in August.
What You Can Do Now
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If you are a registered Democrat in Oklahoma, confirm your runoff eligibility at the Oklahoma State Election Board website. Oklahoma holds closed primaries, meaning only registered Democrats can vote in the Aug. 25 Democratic Senate runoff between Thomas and Priest. The registration deadline for the runoff falls before election day.
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Call the Oklahoma State Election Board at (405) 521-2391 to verify your polling location for Aug. 25 and ask about absentee ballot request deadlines. Runoff turnout drops sharply from primary levels, so early planning matters.
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Research the CD-1 Republican runoff candidates before Aug. 25. Mark Tedford is a sitting Tulsa-area state legislator; Jackson Lahmeyer is a pastor who previously challenged Mullin in the 2022 Senate primary. Voters in CD-1 can review both candidates’ stated positions at Oklahoma Policy Institute.
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Contact your U.S. House representative’s office to ask where they stand on DHS oversight now that Mullin, who held an Oklahoma Senate seat, leads the department. Find your rep’s number through the House directory at house.gov/representatives/find-your-representative.
Sources
- Lahmeyer ends Oklahoma congressional run, Trump instead endorses Tedford — Oklahoma Voice (2026-06-17)
- Voters thin out Oklahoma’s crowded federal races, send two contests to runoffs — Oklahoma Voice (2026-06-17)
- Franklin, Taylor advance to GOP runoff in state superintendent race — Oklahoma Voice (2026-06-17)
Oklahoma Voice: Oklahoma Primary Results Send Two Federal Races to August Runoff
Oklahoma State Election Board: Voter Registration and Primary Rules
Oklahoma Policy Institute: Oklahoma Federal Candidate Tracker