T.W. Shannon, Republican of Oklahoma. Courtesy photo

T.W. Shannon, a member of the Chickasaw Nation, is running for the open U.S. Senate seat in Oklahoma.

Shannon, a Republican, was the first Indian speaker of the Oklahoma House. He stepped down from that leadership position on Tuesday to focus on his Senate campaign.

"It's been a great honor to serve as the House Speaker. Now, I step aside to focus on challenges facing our nation," Shannon said in a message that was posted on Facebook.

If elected, Shannon would be the third enrolled tribal member in Congress. He'd also be the second Chickasaw -- the other is Rep. Tom Cole (R-Oklahoma).

The Senate seat is open due to the retirement and early departure of Sen. Tom Coburn (R-Oklahoma), a former member of the Senate Indian Affairs Committee.

Get the Story:
Oklahoma House Speaker T.W. Shannon steps down for Senate run (The Tulsa World 2/5)

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Chickasaw Nation Gov. Bill Anoatubby won't run for Senate (1/21)
Sen. Tom Coburn of Oklahoma to resign and leave early (1/17)
Chickasaw man on track to serve as Oklahoma House speaker (10/17)