Tancredo was elected to the Colorado House of Representatives in 1976 and served two terms. After working in the United States Department of Education during the Ronald Reagan and George H. W. Bush administrations, he was elected to the United States Congress, and served five terms. He decided to not seek re-election in 2008, instead running a presidential campaign, centered on the issues of illegal immigration and terrorism. He dropped out of the race in December 2007 to assist former Massachusetts Governor Mitt Romney in his campaign for the nomination.