Yglesias argues that Martha Coakley's defeat and the loss of the 60 seat Democratic majority in the Senate doesn't matter that much. And I tend to think he's right, given the tepid support of Obama's agenda by a sizable group of centrist Democrtats. He uncovers this vomit-inducing bit from Indiana's Evan Bayh:
Even before the votes are counted, Senator Evan Bayh is warning fellow Democrats that ignoring the lessons of the Massachusetts Senate race will “lead to even further catastrophe” for their party. [...] “It’s why moderates and independents even in a state as Democratic as Massachusetts just aren’t buying our message,” he said. “They just don’t believe the answers we are currently proposing are solving their problems. That’s something that has to be corrected.” [...] “ The only we are able to govern successfully in this country is by liberals and progressives making common cause with independents and moderates,” Bayh said. “Whenever you have just the furthest left elements of the Dem party attempting to impose their will on the rest of the country — that’s not going to work too well.”
Right, because that's exactly what happened with health care. Far left elements simply imposed their will in the Senate...
One major problem with Senate Democrats is that centrists have the power to enact their agenda on the party as a whole. In both parties, right-wing elements have the most leverage, meaning that the body continues to move to the right. While Ben Nelson may just be a conservative man, senators like Bayh and Lieberman know the power they hold and they want to extend it. That power means more to Bayh than climate change legislation, a national health care plan, or anything else. This cynical power grab inherent in this quote suggests that so long as the Democratic Senate caucus remains as presently constructed, little progressive legislation will get passed, even with 59 Democratic seats.