Bill Ritter easily defeated Republican congressman Bob Beauprez for governor in 2006 in Ritter's first statewide race. Ritter got 57 percent of the vote to Beauprez's 40 percent.

Ritter was appointed Denver district attorney in 1993. He was elected to the position in 1994 and re-elected in 1996 and 2000.

(Last updated by Kristen Wyatt on March 23, 2009.)

Gov. Bill Ritter named Denver Public Schools Superintendent Michael Bennet to fill the Senate vacancy created by the promotion of Sen. Ken Salazar to interior secretary in the Obama administration on Jan. 22, 2009.

Bennet intends to run for a full Senate term in 2010, but he's completely untested at the ballot box, never having run for office before. Bennet spent the early months of his term courting Democratic groups across Colorado, but even insiders at some meetings seemed unsure who he was. Republicans, regrouping after losing a U.S. House seat and the presidential contest in Colorado in 2008, say Bennet is vulnerable, and they plan a vigorous challenge to his re-election.

Bennet's re-election chances got a small boost in March 2009 when one of the state's most prominent Republicans — former U.S. Rep. Scott McInnis of Grand Junction — said he'd likely run against Ritter in 2010, not Bennet. McInnis said he didn't want to return to Washington after six terms in the House.

(Last updated by Kristen Wyatt on March 19, 2009.)

Mark Udall defeated Bob Schaffer in 2008 to win the Senate seat vacated by Wayne Allard. Udall took 53 percent of the vote over Schaffer.

Prior to his Senate win, Udall served a decade in the U.S. House, winning election in 1998 when he defeated Republican Bob Greenlee with 50 percent of the vote. He had served on term in the Colorado House before that.

He won re-election to Congress in 2000 with 55 percent of the vote and in 2002 with 60 percent.

He then defeated Republican Stephen Hackman with 64 percent of the vote in the 2004 general election and Republican Rich Mancuso with 68 percent in 2006.

(Last updated by Joan Lowy on March 27, 2009.)