and the delegation has four Republicans and one Democrat. Oklahoma's U.S. senators are Republicans Jim Inhofe and Tom Coburn , and its U.S. Representatives are John Sullivan (R-OK-1), Dan Boren (D-OK-2), Frank D. Lucas (R-OK-3), Tom Cole (R-OK-4), and James Lankford (R-OK-5). Further information: Political party strength in Oklahoma [ edit ]