Colorado Gov. Bill Ritter (D) will not seek a second term this fall, according to Democratic sources briefed on his decision.
Ritter, elected in a landslide in 2006, had seen his political fate dip considerably in the intervening years, and faced an extremely difficult re-election race against former Rep. Scott McInnis (R) in November.
"Bill Ritter was literally the weakest incumbent in nearly 50 years and his own party was unenthusiastic at best for his reelection," said Colorado Republican party chairman Dick Wadhams. "Colorado has certainly changed from that heady day at Invesco Field."
Democrats are likely to turn to either former state House Speaker Andrew Romanoff or Denver Mayor John Hickenlooper to replace Ritter. Romanoff is currently challenging appointed Sen. Michael Bennet in a Democratic primary and if he could be convinced to switch races would solve two problems for the party.
Colorado is now the eleventh open seat Democrats must defend this year although the other ten seats are being vacated as a result of term limits. Republicans also have eleven open seats of their own to defend. There are 37 governors races on the ballot this fall.
Ritter was a weak choice, so his retirement actually improves Democrats chances of holding this seat because Democrats have a huge bench here to go up against former GOP Congressman Scott McInnis, the presumptive GOP nominee. Still, the GOP is favored.