President Trump on Thursday nominated Sen. Markwayne Mullin (R-Okla.) to serve as secretary of the Department of Homeland Security, creating a vacancy in Oklahoma's U.S. Senate seat and triggering a rapid succession race that could reshape the state's political landscape.
Mullin, who was up for reelection in November, will leave his seat once confirmed. Under a 2021 state law, Gov. Kevin Stitt (R) must appoint a temporary replacement from the same party within 30 days, with that appointee required to sign a pledge not to run in the next election for the seat. The winner of the November special election will take office immediately and begin a new term in January.
The filing period runs April 1-3, with the primary scheduled for June 16 and a potential runoff in late August.
What the Left Is Saying
Progressive Democrats in Oklahoma have largely remained quiet about the upcoming Senate race, focusing instead on the broader implications of Mullin's confirmation to a Trump Cabinet position. The vacancy presents what could be a difficult electoral environment in a state that supported Trump by more than 30 points in 2024.
Oklahoma Democratic strategists have not publicly identified any candidates willing to challenge the likely Republican nominee in what would be an uphill battle in one of the nation's most conservative states. The 2022 special election that sent Mullin to the Senate saw him defeat his Democratic opponent by roughly 27 points.
With no clear Democratic contender emerging, the race is expected to be decided primarily among Republican candidates, many of whom have aligned themselves closely with Trump's agenda.
What the Right Is Saying
Republicans in Oklahoma are quickly positioning themselves for what several strategists describe as an open race with significant implications for the state's political future.
Rep. Kevin Hern (R-Okla.) has emerged as the early front-runner, telling reporters at the Capitol that supporters should 'stay tuned for the announcement next week.' Political strategist Tyler Powell of CSS Partners said he expects Hern to announce Monday or Tuesday, citing intelligence that the congressman is prepared to enter the race.
'I think it starts with Kevin Hern, and it might end with him,' said Pat McFerron, founding partner of CMA Strategies. 'He might be able to clear the field.' McFerron noted Hern's ability to self-fund, saying, 'He's got money he can roll over. He's got personal wealth, he's got good numbers, he's solid with the right side of the electorate.'
Rep. Stephanie Bice (R-Okla.), who unseated former Rep. Kendra Horn (D) in 2020 to win her current seat, is also seriously considering the race. 'I've received encouragement from every corner of this great state to run for the US Senate,' she wrote on X. 'And it's something I'm carefully considering.'
McFerron called Bice a 'formidable' and 'very credible candidate,' though he suggested Hern's entry could clear the field. 'I could not advise anybody to run against him,' he said.
What the Numbers Show
Oklahoma's Senate vacancy comes with specific legal requirements and timeline constraints. Under state law, the temporary appointee must be a registered Republican for at least five years and cannot run in the next election for the seat.
Mullin won his 2022 special election by approximately 27 percentage points over Democrat Madison Horn, reflecting the state's strong Republican lean. The winner of the November 2026 special election will serve the remainder of former Sen. Jim Inhofe's term.
According to political intelligence reported by sources, Hern has approximately $2.5 million in his existing campaign account and is expected to contribute $5 million of personal funds to a potential Senate bid. His personal wealth from his business background provides resources that competing candidates would struggle to match.
Gov. Stitt's approval ratings have suffered following a clash with Trump over the annual governors' meeting in Washington last month. One strategist, Powell, said Stitt's numbers 'are not in a spot where he probably can run,' though constitutional expert Bob Burke noted the governor remains on potential candidate lists due to his name recognition and being term-limited as governor.
The three-day filing window runs April 1-3, with the primary on June 16. If no candidate wins a majority, an August runoff will determine the Republican nominee.
The Bottom Line
The race to replace Mullin presents Oklahoma's most significant political storyline in months, with implications reaching across the state's delegation. Hern enters as the clear early favorite given his financial resources and establishment support, but Bice's entry could create a competitive primary.
Beyond the Senate race, the domino effect extends to potential House vacancies. If either Hern or Bice moves to the Senate, their House seats would open, creating additional races that could reshape Oklahoma's congressional delegation.
Stitt must appoint a temporary senator within 30 days of Mullin's departure. Potential appointees include oil tycoon Harold Hamm, who has reportedly asked for the appointment, along with several Stitt loyalists. That appointee will serve until January and cannot run for the full term, making them a caretaker rather than a candidate.
The condensed timeline means an entire Senate campaign will unfold over roughly nine months, compressing what would normally be a longer election cycle into a rapid sprint that favors well-funded, well-organized campaigns with existing infrastructure.