Stitt meets Trump and GOP leaders as Oklahoma prepares to fill Mullin’s vacated U.S. Senate seat

An unexpected vacancy reshapes Oklahoma’s 2026 federal election calendar

Oklahoma’s next U.S. Senate contest accelerated this month after President Donald Trump selected Sen. Markwayne Mullin for a Cabinet role as secretary of the Department of Homeland Security, setting in motion the process to fill a soon-to-be vacant Senate seat. The development prompted Gov. Kevin Stitt to travel to Washington for meetings with Trump and Republican leaders as the state prepares for both a temporary appointment and a fast-moving election cycle.

Mullin, elected in 2022 to complete the final years of the late Sen. Jim Inhofe’s term, is up for election again in 2026. If Mullin leaves the Senate to join the administration, Oklahoma law gives Stitt the authority to name an interim replacement.

How the replacement process works under Oklahoma’s current law

The vacancy would be filled in two steps: an appointment followed by an election later this year. Under the current statute, the governor’s appointee would serve only temporarily and is barred from running in the next election for the seat. That restriction eliminates the typical advantage of incumbency and increases the likelihood of a crowded Republican primary in a state where the party is strongly favored in statewide federal races.

• Stitt appoints a temporary U.S. senator after the vacancy occurs.
• The appointed senator serves until the 2026 election is decided and certified.
• The appointee is not permitted to run for the seat in that election.

Filing deadlines and the early shape of the field

State election timelines are already driving decisions by prospective candidates. Oklahoma’s candidate filing period for the 2026 election is scheduled to begin April 1, compressing fundraising, endorsements, and coalition-building into a matter of weeks. The vacancy is expected to trigger downstream contests as well, including potential openings in Oklahoma’s congressional delegation if sitting House members pursue the Senate seat.

In Washington, Rep. Kevin Hern of Tulsa has moved toward a Senate campaign, a step that has also drawn attention inside the U.S. House to the leadership role he currently holds within the Republican conference. Other Republicans with established statewide networks or recent campaign experience have been widely discussed as possible contenders, including sitting members of Congress and former state officials.

Stitt has said he intends to appoint a conservative aligned with the administration’s priorities to serve on an interim basis.

What Stitt’s meetings signal

Stitt’s discussions with Trump and Republican leaders come at a moment when the selection of an interim senator could influence party dynamics even if the appointee cannot seek the seat. The temporary senator will still cast votes during a consequential period in Washington and may shape committee ratios and floor timing while Oklahoma’s campaign unfolds.

With the appointment decision and the April filing window approaching, Oklahoma Republicans are entering a compressed and high-stakes sprint that will determine both a short-term Senate vote and a long-term successor elected statewide in November 2026.