Oklahoma Governor Appoints Energy Executive to Fill Senate Vacancy

Alan Armstrong will serve through the end of the year after Markwayne Mullin's confirmation as Homeland Security Secretary

Mar. 24, 2026 at 7:10pm

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Oklahoma Governor Kevin Stitt has appointed energy executive Alan Armstrong to serve in the U.S. Senate through the end of the year, filling the vacancy left by Republican Markwayne Mullin's confirmation as the new Homeland Security Secretary. Armstrong, the chairman and former CEO of pipeline operator Williams Companies, will not run for a full term in the upcoming November election.

Why it matters

The appointment of an energy industry executive to the Senate seat raises questions about the influence of the oil and gas sector in Oklahoma politics, particularly as global energy markets are disrupted by the ongoing Iran war. Armstrong's background and connections to the state's governor also highlight the political dynamics at play in the selection process.

The details

Governor Stitt, who had pledged to appoint a "conservative voice" to the seat, elevated Armstrong, a longtime supporter who has donated the maximum amount allowed to Stitt's campaigns. Armstrong has spent his career at Williams Companies, a major pipeline operator based in Tulsa, and served as the company's CEO from 2011 until transitioning to executive chairman last year. He has never held elected office before.

  • On March 24, 2026, Oklahoma Governor Kevin Stitt appointed Alan Armstrong to the U.S. Senate seat.
  • Markwayne Mullin was confirmed as the new Homeland Security Secretary on March 23, 2026, creating the Senate vacancy.

The players

Alan Armstrong

The chairman and former CEO of Williams Companies, a major pipeline operator based in Tulsa. He has been appointed by Governor Stitt to serve the remainder of Markwayne Mullin's U.S. Senate term through the end of 2026.

Kevin Stitt

The Republican Governor of Oklahoma who appointed Alan Armstrong to the U.S. Senate seat. Stitt had pledged to appoint a "conservative voice" to fill the vacancy.

Markwayne Mullin

The Republican U.S. Senator from Oklahoma who was confirmed as the new Homeland Security Secretary, creating the Senate vacancy that was filled by Alan Armstrong.

Dewey Bartlett Jr.

The former mayor of Tulsa who described Armstrong as an "even-tempered individual" more likely to build consensus than be driven by political ideology.

Kevin Hart

The Republican U.S. Representative who quickly announced his candidacy for the Senate seat and has been endorsed by President Trump.

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What they’re saying

“I think that certainly is a great approach, finding consensus for making a decision.”

— Dewey Bartlett Jr., Former Tulsa Mayor

What’s next

Republican U.S. Representative Kevin Hart has already announced his candidacy for the Senate seat and received an endorsement from President Trump. The November 2026 election will determine who will serve a full term in the Senate.

The takeaway

The appointment of an energy industry executive to the Senate seat highlights the influence of the oil and gas sector in Oklahoma politics, particularly as global energy markets face disruption. It remains to be seen whether Armstrong's consensus-building approach will prevail or if the seat will be contested in the upcoming election.