Parker Griffith's switch today is a good reminder that there are more people on the conservative side of the party spectrum unhappy with it than the liberal side, even though the left and the blogosphere tend to get more media attention for their unhappiness.
On our last poll 27% of Democrats expressed disapproval of the party's Congressional leadership. Out of that group 49% said they were opposed to the health care bill with only 44% in support, and 85% of those opposed said it was because the bill created too much government involvement in health care.
Also while 38% of all Democrats are liberals and 12% are conservatives, among those unhappy with Congress 24% are conservatives and just 21% are liberals.
Parker Griffith is more representative of the Democrats unhappy with their party than a liberal blogger mad about the loss of the public option.
That said, I don't think Griffith had any shot at reelection as a Democrat given the highly conservative nature of his district and it's probably better for the party to just lose his seat now instead of losing it after blowing a million dollars on it a year from now. I hate to be a defeatist but depending on initial numbers I'm not sure I'd spend a lot of money defending Bobby Bright, Walt Minnick, or Frank Kratovil either. The odds are very much stacked against them for reelection anyway and if they're not going to be reliable votes for core Democratic initiatives it might be better to spend that money elsewhere.