Matthew Yglesias expresses the political logic for passing health care reform, succinctly and, in my opinion, persuasively:
If you’ve already voted for health reform, which a majority of House members and 59 Senators have, then you’re already going to get hit with 100 percent of the hits that accrue to people who vote for Obamacare. Nobody is going to care about the fine nuances of “senate bill” versus “house bill” or whatever. It’s Obamacare and you’re going to get hit.
The question is whether you’d rather get hit for your participation in a discredited failure that’s been abandoned by its own architects, or whether you’d rather get hit for participation in a controversial but successful effort to fulfill the decades-long promise of universal health care? I don’t think it’s even close. If the bill passes, that generates a positive narrative around the bill that can compete with the negative narrative. If it fails, then you’ve got all the negative narratives but you also add on a new bonus negative narrative of gridlock and failure. If it passes, all the groups out there that like the bill can come out and explain to people about the good things in it. If it fails, then they all go running for the hills but your enemies still get to emphasize the unpopular parts. In other words, voting “yes” on Obamacare is politically problematic but it’s already happened now the question is whether your “yes” vote buys you an actual bill to stand and fight on.