Because no one blamed the Dems for the messes they have made for the last 2 years. It was all because of Bush.
Bush has presided over one of the most uninspiring insipid group of political appointees ever appointed by an administration. For the party that is supposed to know how to run things they knew how to run nothing. There job is to make public policy choices - what will be done and what won't be done. They didn't. They just sat there and let the bureaucrats do their thing. Harriet Miers nomination as a SC justice was not one of his worst choices. It was one of his best, very sadly. Fortunately, in that case we had folks who said not good enough, Mr. President. We needed to say the same for about 1000 other political appointees.