 Barred by term limits from seeking reelection to a second term in 1997, he worked in the private sector until the 2000 election in which he ran for the United States Senate, defeating two-term Democratic incumbent Chuck Robb.Allen ran for reelection in the 2006 election, but after a close and controversial race, he was defeated by Democratic former U.S. Secretary of the Navy Jim Webb.When Webb decided to retire, Allen ran for his old seat again in the 2012 election but was defeated again, this time by Democratic former Governor Tim Kaine.