2014 Colorado Senate Race
The Democratic group looks to defend Sen. Mark Udall (D) from Koch brothers-backed attacks.
The Colorado senator claims his new opponent engaged in dealmaking to clear the GOP field.
The congressman's decision would give GOP a top-tier candidate against Sen. Mark Udall (D).
Their pick is a blow to Ken Buck, who the group endorsed in 2010 and is now running again.
Forty percent said they'd be less likely to vote for the Colo. Dem if Obama campaigns.
The Colorado Democratic senator raised more than $1 million in the fourth quarter.