TULSA -- Oklahoma House Speaker T.W. Shannon has formally entered the GOP race for the open U.S. Senate seat in Oklahoma, while Republican U.S. Rep. Jim Bridenstine said he won't be running for the position.
Bridenstine said Wednesday he wouldn't run for the Senate seat left open by Sen. Tom Coburn's resignation .
The first-term congressman made his announcement moments before Shannon formally declared his candidacy at an event in Tulsa.
Shannon will join two-term U.S. Rep. James Lankford and two lesser-known Republicans in the race for the GOP nomination.
A Democrat hasn't been elected to an open U.S. Senate seat in Oklahoma since David Boren in 1978, and Republicans are heavily favored to maintain it.
No Democrats have formally announced.
A special election to fill Sen. Coburn's seat has been set on the same dates as Oklahoma's primary and general elections this year.