Marc Ambinder identifies Health Care Reform as a classic example of the kind of policy fight a president can’t win.

I think he’s right. Socialized health care is a goal that the left can neither relinquish nor hope to win.

As the prospects for bipartisan agreement in the Senate fade, the need for Obama to unify Democrats will increase. Right now, though, he is losing Democrats from both wings of the party, even as independents soften and conservatives mobilize. Obama’s ratings in the Pew survey declined slightly from July to August among moderate Democrats (down two percentage points) and sharply among liberal Democrats (down nine percentage points).

These poll numbers suggest that health care is becoming the classic issue that wounds a president: one that unites his opponents and divides his own side. Obama probably has little hope of changing the first half of that equation; when Congress returns he’ll probably need to focus more on improving the second.