The 2010 United States Senate election in Colorado took place on November 2, 2010, alongside other elections to the United States Senate in other states as well as elections to the United States House of Representatives and various state and local elections. In December 2008, President-elect Barack Obama nominated incumbent U.S. Senator Ken Salazar as Secretary of the Interior. After Salazar resigned from his seat, Democratic governor Bill Ritter appointed Denver Public Schools Superintendent Michael Bennet to fill the seat.
Bennet won a full term, defeating former state House speaker Andrew Romanoff in the Democratic primary, and Republican nominee Ken Buck in the general election. With a margin of 1.7%, this election was the second closest race of the 2010 Senate election cycle after the concurrent one in Illinois.
Democratic primary
Candidates
Declared
Michael Bennet, incumbent U.S. Senator
Andrew Romanoff, former speaker of the Colorado House of Representatives
Endorsements
Bennet
President Barack Obama
U.S. Senator Russ Feingold
Congresswoman Diana DeGette
Congressman Ed Perlmutter
Congresswoman Betsy Markey
U.S. Senator Mark Udall
Congressman Jared Polis
Congressman John Salazar
Former U.S. Senator Gary Hart
Governor Bill Ritter
Romanoff
Former president Bill Clinton
Polling
Results
Republican primary
Candidates
Declared
Ken Buck, Weld County District Attorney
Jane Norton, former Lieutenant Governor of Colorado
Declined
Bob Beauprez, former U.S. Representative for Colorado's 7th congressional district Troy Eid, U.S. Attorney for United States District Court for the District of Colorado Ryan Frazier, Aurora city councilman
Withdrew
Tom Wiens, former state senator
Other
Three other candidates were defeated at the Republican state convention and were not on the primary ballot: Cleve Tidwell, businessman Robert Greenheck Steve Barton
Endorsements
Polling
Results
Libertarian primary
Candidates
John Finger
Mac Stringer
Results
General election
Candidates
Major
Michael Bennet (D), incumbent U.S. Senator
Ken Buck (R), Weld County DA
Minor
Bob Kinsey (G) (campaign site, archived November 4, 2010, PVS) Charley Miller (I) (campaign site, PVS) J. Moromisato (I) (campaign site, PVS) Jason Napolitano (I) (PVS) Mac Stringer (L) (campaign site , PVS) Bruce E. Lohmiller (G) (Write-in) (Congress.org) Michele M. Newman (I) (Write-in) () Robert Rank (R) (Write-in) () campaign site, () YouTube campaign video Source: Official Candidate List
Campaign
This was one of the most expensive elections in the nation, as more than $30 million was spent by outside organizations. Conservative third party groups hammered Bennet for voting 92% of the time with the Democratic leadership, including voting for healthcare reform and the stimulus package. Liberal third party groups called Buck extremist. Bennet focused on attacking Buck's views on abortion, which he believed should be banned including those of cases of rape and incest. He was also attacked for wanting to eliminate the 17th Amendment and refusing to prosecute an alleged rapist as Weld County district attorney. Planned Parenthood mounted a mail campaign, targeting women voters with the warning that "Colorado women can't trust Ken Buck." Bennet won the women vote by 17 points according to exit polls. After the election, Buck conceded to the Denver Post that the main reason why he lost is because of social issues.
Debates
September 12: Sponsored by Club 20 in Grand Junction
Predictions
Polling
Fundraising
These totals reflect the campaign accounts of the candidates themselves, and do not include independent expenditures by other groups.
Results
Counties that flipped from Democratic to Republican
Garfield (largest municipality: Glenwood Springs) Bent (Largest city: Las Animas) Mineral (Largest city: Creede) Rio Grande (Largest city: Monte Vista) Archuleta (Largest city: Pagosa Springs)
Counties that flipped from Republican to Democratic
Chaffee (largest city: Salida) Ouray (largest city: Ouray)