Clarence William "Bill" Nelson (born September 29, 1942) is the senior United States Senator from the state of Florida. A member of the Democratic Party, he is a former U.S. Representative and former Treasurer and Insurance Commissioner of Florida. He is a leader in air and space policy, and in 1986, he became the second sitting member of the United States Congress to fly in space.
Born in Miami, Nelson attended the University of Florida before transferring to Yale University. He went on to receive his law degree from the University of Virginia. In 1965, he joined the U.S. Army Reserve; he served on active duty from 1968 to 1970, attaining the rank of captain, and left the following year. Nelson was admitted to the Florida bar in 1968, and began practicing law in Melbourne in 1970. In 1971, he worked as legislative assistant to Governor Reubin Askew.
In 1972, Nelson was elected to the Florida House of Representatives. He won re-election in 1974 and 1976. Nelson was elected to the U.S. House of Representatives in 1978. He served in the U.S. House from 1979 to 1991. In January 1986, he flew as a Payload Specialist on the Space Shuttle Columbia. After a failed gubernatorial race in 1990, he successfully ran for the office of Treasurer and Insurance Commissioner of Florida in 1994 and served for six years. In 2000, Nelson ran as a Democrat for the U.S. Senate seat vacated by retiring Republican Senator Connie Mack. In the Senate he is generally considered a social moderate and economic liberal. He was re-elected in 2006 with 60 percent of the vote.