John William Warner III was an American lawyer and politician who served as the United States Secretary of the Navy from 1972 to 1974 and as a five-term Republican U.S. Senator from Virginia from 1979 to 2009. He served as Chairman of the Senate Armed Services Committee from 1999 to 2001, and again from 2003 to 2007. Warner also served as the Chairman of the Senate Rules Committee from 1995 to 1999.

The 2008 United States Senate election in Virginia was held on November 4, 2008. Incumbent Republican Senator John Warner decided to retire instead of seeking a sixth term. Former Governor Mark Warner (unrelated) won the open seat by more than 31 percentage points. Warner became the first Democrat to win this seat since 1966. This was also the first time since 1964 that the state voted simultaneously for a Democratic presidential candidate and a Democratic Senate candidate, having voted for Barack Obama in the presidential election, albeit by a far lesser margin. This was Virginia's first open-seat election since 1988. Mark Warner's inauguration marked the first time since Harry Flood Byrd Jr. left the Democratic Party to become an independent in 1970 where Democrats held both of Virginia's Senate seats.