Rep. Cory Gardner (R-Colo.) is officially launching his campaign against Sen. Mark Udall (D-Colo.), giving Republicans a top-tier recruit that could help them expand the Senate playing field.
Gardner held an event in Denver on Saturday to publicly declare the run. The Hill reported on Wednesday that he would run for the seat.
His decision to challenge Udall, months after he said he wouldn't, gives Republicans a potentially formidable candidate for the race and could help boost their chances for a Senate takeover.
Udall's poll numbers have been less than stellar, but until now Republicans struggled to land a serious recruit against him and faced a crowded field of B-list candidates.
Republicans need to pick up six seats for Senate control, and putting Colorado in play could help them do so.
Gardner's campaign will also help clear the field. Two Republican candidates already in the Senate race, 2010 Senate nominee Ken Buck (R) and Amy Stephens (R), plan to drop out and endorse him.