U.S. Rep. James Lankford defeated former Oklahoma Speaker of the House T.W. Shannon in Tuesday’s GOP Senate primary. In November, Lankford will face the Democratic nominee for the state’s open U.S. Senate seat.

The seat became available after GOP Sen. Tom Coburn announced plans to step down with two years remaining on his term due to a recurring cancer battle.

Lankford is expected to win the seat easily in the deep-red state; Republicans hold every statewide office and both state legislative chambers.