The retirement of Sen. Ben Nighthorse Campbell has been announced

The senior senator from Colorado has announced his retirement today, after first being elected in 1992 as a Democrat.  Soon thereafter, he switched to the GOP.  Word is that the GOP governor, Bill Owens, may join the race now (he is serving his last term as governor).  Additionally, Rutt Bridges, who just announced on the Dem side, may be joined by Congressman Mark Udall, who previously "flirted" with the race.  I presume that if Gov. Owens jumps in, he will be the favorite, but this is now yet another GOP open seat that they have to defend, this time late in the game.  Curious how this race will turn out.  

Link to the Denver Post article on the announcement:

http://www.denverpost.com/Stories/0,1413,36~64~1994067,00.html