Since 1890, 20 senators have switched parties. Here are some recent ones:
Joe Lieberman, Conn.: Reelected in 2006 as an independent after losing the Democratic primary amid intense antiwar sentiment.
James Jeffords, Vt.: Infuriated GOP leaders in 2001 when he became an independent, saying the party had become too conservative for him. The move gave Democrats control of the Senate until the 2002 election.
Robert Smith, N.H.: Went from Republican to independent in July 1999, then back to Republican that November.
Ben Nighthorse Campbell, Colo.: Democrat, 1993-1995; Republican, 1995-2005.
Richard Shelby, Ala.: Democrat, 1987-1994; Republican, 1994-present.
For a complete list, go to www.tinyurl.com/changeparties.
