KUSA - Republican party officials in Colorado confirm to 9NEWS that Rep. Cory Gardner (R-Colorado) is entering the race for U.S. Senate, hoping to oust incumbent Sen. Mark Udall (D-Colorado).
At the same time, Weld County DA Ken Buck is dropping his bid to challenge Udall and is running for Gardner's House seat instead, GOP officials said.
The Udall campaign did not mention Gardner by name when asked to comment.
"We need to replace Mark Udall in the Senate, and I believe Congressman Cory Gardner is in the strongest position to make that happen," Buck said in a statement. "The Senate race has never been about me but about helping change the direction of the country. I hope to have the opportunity to lead the fight for limited government and fiscal responsibility as a member of the U.S. House of Representatives."
"Mark spends every day working to protect Colorado's special way of life," Udall campaign spokesman Chris Harris said. "Mark looks forward to debating the important issues that impact our future."
The move firmly establishes Gardner as a front-runner in a crowded GOP field that also includes state legislators Amy Stephens, Randy Baumgardner, and Owen Hill.
Hill was sharply critical of the announcement that Garner and Buck are swapping races.
"Two weeks ago, Cory tried to push me out of the race," Hill said.
When asked if he worried about upsetting the GOP by not deferring to a sitting member of Congress, Hill replied, "What people should be angry about is that we keep doing back-room, insider deals like this one."
Baumgardner tells 9NEWS he's also staying in the Senate race, but made it clear he's not upset at Gardner for jumping in this late.
A vocal critic of the Affordable Care Act, Gardner is a rising star in Republican circles and his entrance into the race signals that the GOP sees vulnerability for incumbent Sen. Mark Udall.
Aside from instantly raising the profile of the election for Udall's seat, Gardner's decision means Colorado will have a House race in November with no incumbent, though a Democrat would be a clear underdog in the largely rural district that encompasses Colorado's Eastern Plains.
State Sen. Greg Brophy (R-Wray), tells 9NEWS he will not be jumping into the race for Gardner's House district.
"I'm not running because I want an office," Brophy said. "I'm running for Governor."
Democrats pounced on the news, echoing Hill's sentiment.
"Given Republicans' back room wheeling and dealing," wrote Colorado Democratic Party Chair Rick Palacio. "Coloradans will see that Cory Gardner is simply a Ken Buck-radical who is neck deep in Washington sleaze."
Udall has been doing heavy fundraising lately, with $4.7 million on hand. By contrast, Gardner has $877,000.
If others share his faith in Udall's vulnerability, Gardner's numbers should grow in a hurry.