From 1989 until 1997, Geren served for four terms in the United States House of Representatives. He was first elected in a special election to succeed former Speaker of the HouseJim Wright. He narrowly defeated Republican candidate, well known Fort Worthallergist Bob Lanier (not to be confused with the mayor of Houston of the same name). Geren was re-elected for three more terms, but opted not to run in 1996. He was succeeded by Kay Granger.
While in Congress, Geren was credited with coining the term "Blue Dog Democrat". Moderate and conservative Democrats in Congress chose to name their group after this term, creating the Blue Dog Coalition. Geren opined that the members had been "choked blue" by "extreme" Democrats from the left.[4] It is related to the political term "Yellow Dog Democrat," a reference to southern Democrats said to be so loyal they would even vote for a yellow dog if it were labeled a Democrat.
Department of Defense
Geren joined the Department of Defense in September 2001 to serve as Special Assistant to the Defense Secretary with responsibilities in the areas of inter-agency initiatives, legislative affairs and special projects.
Geren was the 28th Undersecretary of the Army, a post he assumed on February 21, 2006, following his nomination by President George W. Bush and confirmation by the United States Senate. As the Undersecretary, Geren was the Army's No. 2 civilian leader. He served as the deputy and senior advisor to the Secretary of the Army and was Acting Secretary in the absence of the Secretary.