David Ferdinand Durenberger (August 19, 1934 – January 31, 2023) was an American politician and attorney. Durenberger represented Minnesota in the United States Senate as a Republican from 1978 to 1995. He left the Republican Party in 2005 and became a critic of it, endorsing Democratic presidential nominees Hillary Clinton and Joe Biden in 2016 and 2020, respectively. Early life Durenberger was born in St. Cloud, Minnesota, the son of Isabelle Marie (née Cebulla) and George Gephard Durenberger. He was a Roman Catholic of German and Polish descent. His father was the athletic director and a coach at Saint John's University in Collegeville, Minnesota, and the family lived on campus. Durenberger graduated from St. John's Prep School there in 1951, and from the university in 1955. He attended the University of Minnesota Law School and earned his Juris Doctor in 1959. At St. John's he was the top-rated cadet in his ROTC class, and after college was a lieutenant in the U.S. Army Counter-Intelligence Corps in 1956 and a captain in the United States Army Reserve from 1957 to 1963. Professional career After law school, Durenberger was employed by a South St. Paul law firm with strong political connections. It had been founded in 1929 by Republican Harold Stassen, later the governor of Minnesota from 1939 to 1943, and Elmer Ryan, a Democrat who was member of the U.S. House of Representatives from 1935 to 1941. When Durenberger joined it was headed by Harold LeVander. The firm took the name LeVander, Gillen, Miller and Durenberger. LeVander, a Republican, was elected governor of Minnesota in 1966 and took office in January 1967, and Durenberger became his executive secretary from then until the end of LeVander's term in 1971. He then joined the H.B. Fuller Company as in-house counsel, corporate secretary, and manager of international licensing until 1978. He also served as chair of the Metropolitan Open Space Advisory Board from 1972 to 1974 and was on the Minnesota State Ethical Practices Board from 1974 to 1978. United States Senate On November 7, 1978, Durenberger was elected to the United States Senate in a special election to complete the unexpired term of Senator Hubert Humphrey, who died earlier in the year; Humphrey's wife Muriel held the seat until Durenberger's election. Durenberger was reelected in 1982 and again in 1988, defeating Mark Dayton and Minnesota Attorney General Skip Humphrey, respectively. In the 99th