The short answer
Oklahoma Gov. Kevin Stitt is expected to appoint former Williams CEO Alan Armstrong to the U.S. Senate when Sen. Markwayne Mullin leaves his seat upon confirmation as Department of Homeland Security secretary, according to NOTUS and News On 6.
NOTUS reports Stitt, Armstrong and former President Donald Trump are meeting at Mar-a-Lago to discuss the potential appointment and secure Trump’s support.
No official decision has been announced.
Who is Alan Armstrong?
Alan Armstrong is a longtime Oklahoma energy executive and former leader of one of the state’s largest companies.
CEO of Tulsa-based Williams (2011–2025)
Executive chairman since June 2025
Leader in the natural gas industry
Williams reported nearly $12 billion in revenue last year
Who else was considered?
Multiple media reports say the decision was recently narrowed to three candidates:
Alan Armstrong (Williams executive)
Harold Hamm (Continental Resources founder)
Dustin Hilliary (businessman, newly appointed OU regent)
Hilliary recently accepted a position on the University of Oklahoma Board of Regents and will step down from his role on the Oklahoma State Regents board.
What does “temporary appointment” mean?
If selected, Armstrong would:
Serve as an interim U.S. senator
Likely agree not to run in the next election cycle
Hold the seat until voters elect a permanent replacement
Why Trump matters
The appointment could depend on Donald Trump's support.
According to reports, Trump has favored Harold Hamm for the role, making his backing a key factor in Stitt’s final decision.
What happens next
Mullin must first be confirmed to leave his Senate seat
Stitt would then officially announce an appointment
The appointee would be sworn in shortly after
Until then, the situation remains fluid.
Recap
Alan Armstrong has emerged as the leading candidate to replace Markwayne Mullin in the U.S. Senate — but the final call may come down to politics, timing and Trump’s influence.