DENVER (AP) -- In a switch that shakes up the Senate contest in Colorado, Rep. Cory Gardner will forgo re-election to challenge Democratic incumbent Mark Udall while GOP front-runner Ken Buck drops out of the primary race to seek Gardner's House seat, Republican officials said Wednesday.
"I have talked to Cory and I feel that he would be a great candidate for the U.S. Senate," Buck said in an interview. "I am stepping aside so he can run against Mark Udall."
Gardner declined to comment as he left the U.S. Capitol.
With Gardner in and Buck out of the Republican primary, the political landscape changes dramatically for Democrats as they defend their Senate majority and Republicans battle to gain the six seats they need to control the chamber.
The news elated Republicans in Washington and Colorado, where some party members were concerned about Buck's prospects. He narrowly lost his challenge against the state's junior senator, Michael Bennet, in 2010.
Gardner, 39, was viewed as his party's best challenger to Udall, but last year he said he wouldn't enter the race. At that time, Udall was seen as having a safe seat and Gardner's refusal to run was yet another indication that Colorado, once a Republican-leaning swing state, was trending to Democrats.
Republicans are expected to easily hold Gardner's House seat.
"He is exactly the kind of young, articulate, substantial Republican who can not only win a statewide election, but can break this 12-year stranglehold Democrats have had on this state," said Dick Wadhams, former chairman of the Colorado Republican Party.
Gardner would enter the race with $876,000 in his House campaign account that he can immediately use in the Senate contest -- more money than the other three major Republican candidates had combined.
One of the other GOP candidates, state Sen. Owen J. Hill, said Wednesday that Gardner had called him two weeks ago urging him to leave the race. "This is exactly why Republicans keep losing, because we're cooking these backroom insider deals," Hill said in an interview, vowing to stay in.
Republican state Rep. Amy Stephens told the Colorado Springs Gazette she planned to drop out of the Senate race and support Gardner.
Matt Canter of the Democratic Senate Campaign Committee said Gardner is not more moderate than Buck. Canter said Gardner "wants to decimate Medicare, slash education and even make common forms of birth control illegal."
Associated Press writers Charles Babington and Donna Cassata in Washington contributed to this report.
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