Former member of Congress
Markwayne Mullin
Republican · Former U.S. Senator from Oklahoma · 2023–2026
What happened
Markwayne Mullin left the U.S. Senate in February 2026. Left the Senate to become U.S. Secretary of Homeland Security.
No longer serving, so this page is a record rather than a live countdown. Source, checked September 18, 2026.
Who holds the seat now
Alan Armstrong (Republican) now holds this Oklahoma Senate seat.
Frequently Asked Questions
Is Markwayne Mullin still in Congress?
No. Markwayne Mullin left the U.S. Senate in February 2026.
Who replaced Markwayne Mullin?
Alan Armstrong (Republican) now holds this Oklahoma Senate seat.
When did Markwayne Mullin leave the Senate?
February 2026, after serving in Congress since 2023.