From 1965 to 2006, ten state senators have been selected to serve as president pro tempore over the 41-year period that would have allowed for the election of 22 presidents pro tempore. Of those ten, only James E. Hamilton of Poteau, Oklahoma, and Cal Hobson of Lexington, Oklahoma, served only one full single term. Hamilton was an unsuccessful candidate for the United States Senate in 1980, and he eventually returned to politics as a state representative, where he chaired the appropriations committee. Hobson won reelection to the office of president pro tempore, but resigned shortly thereafter when the Oklahoma Senate Democratic Caucus voted to allow him to resign or be ousted due to alcohol abuse during the 2005 legislative session. After completing his treatment for alcoholism, Hobson sought unsuccessfully to be the Democratic nominee for Lieutenant Governor of Oklahoma in 2006.