Oklahoma became the 46th state in the Union on November 16, 1907. The state’s first two senators, Robert L. Owen and Thomas P. Gore, took office on December 11, 1907. Oklahoma’s longest-serving senators include James Inhofe (1994-present) and Donald L. Nickles (1981-2005). Among those who rose to leadership positions are Robert Owen, who served as Democratic Conference secretary, and Don Nickles, who served as Republican Party whip and Policy Committee chairman.