Colorado

The Rocky Mountain State's Aug. 10 primary election highlighted divisions within both parties.In the Senate race, tea party-backed Ken Buck, the Weld County district attorney, handily defeated former Lt. Gov. Jane Norton, the Republican establishment candidate. Buck now hopes to unseat incumbent Democrat Michael Bennet, who has President Obama's endorsement. Bennett survived a strong primary challenge from former state House Speaker Andrew Romanoff, who was backed by former President Bill Clinton.Bennet is a rookie officeholder appointed a year and a half ago to replace to replace Ken Salazar, who was named Obama's Interior secretary. Bennet used to be chief of staff for Denver Mayor John Hickenlooper, the Democrats' gubernatorial nominee. Republicans saw an opportunity to pick up a governor's seat when Democrat Bill Ritter decided not to seek a second term. But GOP nominee Dan Maes is a tea party activist and party outsider, and former Congressman Tom Tancredo's late entry into the race as a third-party candidate could split the Republican vote.The tightest House race is in the 4th District, where freshman Democrat Betsy Markey is seeking re-election. Obama won Colorado in 2008.