Public Policy Polling, which nailed the Massachusetts Senate vote, is out with a new survey:

Barack Obama’s approval rating is in negative territory. 47% of voters in the country express unhappiness with the job he’s doing while 46% give him good marks. 81% of Democrats, 43% of independents, and 11% of Republicans think he’s doing well. While he retains ratings over 70% with both African Americans and Hispanics, he’s now at a negative 36/57 spread with white voters. Obama’s health care plan continues to be part of his popularity problem. 49% of voters in the country are opposed to 40% in favor. Republicans are much stronger in their opposition than Democrats are in their support. 41% of voters say that Obama has lived up to their expectations while 49% think he has not. The biggest drop between his approval and the feeling that he’s met expectations is with independents.

It’s that collapse of support among independents that’s so alarming to Democrats. This is certainly not the only evidence we’ve seen of independents fleeing the president and his party. For months now, the president’s support among independents has been cratering. Moreover, in three successive high-profile elections — in New Jersey, Virginia, and Massachusetts — independents have voted in large numbers against the Obama agenda and for the Republican candidate. It’s a recipe for disaster for many Democrats who must rely to one degree or another on a coalition of independents and Democrats to keep them in office.

It’s the mirror image of the Republicans’ travails in 2006 and 2008, when they lost all but their core supporters, and so depressed those voters that they gave their opponents the turnout and enthusiasm advantage. It’s not impossible for Democrats to get these voters back. Bill Clinton did it with welfare reform and with a dramatic reorientation of his presidency. We’ll see if Obama can do so as well, and whether his party must first experience a drubbing in the midterm elections.