Trump’s selection of Senator Markwayne Mullin (OK) to replace DHS Secretary Kristi Noem could cost Republicans a Senate seat for nearly nine months while holding a very slim majority.
Oklahoma statute (Title 26, § 12-101) prohibits gubernatorial appointments for U.S. Senate vacancies occurring within 84 days of the primary election; with the June 16, 2026 OK primary approaching, Mullin’s seat could remain vacant until after the November midterms.
Kristi Noem’s departure as DHS Secretary is effective March 31, 2026 (per Trump’s indication that Mullin should start at the end of the month), this shifts the timeline for Senator Markwayne Mullin’s potential resignation from his Senate seat. Mullin would likely resign around that date to assume the DHS role on or about April 1, creating the vacancy then.
Oklahoma law (Title 26, § 12-101) allows the governor to appoint a temporary replacement for a U.S. Senate vacancy until a special election, but prohibits such an appointment if the vacancy occurs within 83 days before the next primary election (June 16, 2026). This is designed to align the special election with the regular cycle for the seat (which is up in 2026 anyway) without interim appointments too close to the vote.
We are currently 103 days before the primary, just outside the 83-day window. IF Mullin resigns in the next two weeks, an immediate vacancy would allow a gubernatorial appointment to keep the seat filled until the November election winner takes office in January 2027.
But, March 31, 2026 is only 77 days before the primary—within the 83-day window, so no appointment would be permitted. The Senate seat would remain vacant from late March until January 2027 (about 9 months), costing Republicans a crucial vote in a slim Senate majority.
So, does Mullin resign NOW, assuming the Senate will confirm his nomination, and allow Oklahoma Governor Stitt to quickly fill his seat? Or does he wait and see if his fellow senators confirm his nomination and thereby cost Republicans are crucial vote for the remainder of the year? The clock is ticking!!
By the way, Oklahoma law also essentially requires the person appointed to fill a vacancy in the US Senate to swear that they will not seek the full-term election. Thus, the Republican governor would be required to appoint a “placeholder,” who would not seek election in the primary in June for the November general election.
Steve Gill is editor and publisher of TriStar Daily.
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