...One more thing (on the Angell piece, and do read Cohn and Klein's posts).
Liberals have expressed a lot of frustration about which policy positions are considered mainstream, and which are considered liberal, radical left, conservative, and far conservative. Liberals -- I'm not going to look for a citation here, but anyone who reads liberal blogs will recognize this -- believe that conservatives have succeeded in moving the "center" well to the right over the last couple of decades, mainly through pure bullying tactics.
I'm not sure to what extent that's true, but I do know what liberals can do if they want to move the center on health care reform: pass the health care reform bill.
Once the bill passes and is implemented, the center changes. Instead of the question become whether or not to achieve universal coverage, the question immediately changes to whether that coverage is adequate or not. Instead of whether the nation can afford to cover additional people, the question immediately changes to how to support coverage for everyone. It's not clear at all to me that liberals win (substantively or politically) on those fights, but the entire field of battle shifts significantly, and as permanently as anything can get, in the direction liberals want.