Atrios is optimistic*:
Federal judge strikes down whole law, sez mandate is unconstitutional and cannot be severed from rest of law.
Maybe we’ll return to my crazy idea to pay for it out of taxes.
The problem is, though, that if the entire bill is struck down Humpty Dumpty isn’t going to be reassembled (let alone in a more pleasing form) for the foreseeable future. First, it’s likely to be be quite a while before we have 60th vote in the Senate as liberal as it was in early 2010 to go with a substantial Democratic House majority and a Democratic president. And, second, the new legislative coalition would have to be more liberal, as the most obvious way of buying off the vested interests without direct tax hikes is no longer available. So the Supreme Court striking down the ACA in its entirety would be very bad — as I suspect Duncan would agree, a decade or three more of the status quo in exchange for a slightly more rational bill isn’t a good tradeoff.
If the mandate is eliminated without severance, though, that’s a different story. As long as the pre-existing conditions ban remains in place (and it would be nearly impossible politically to get rid of it), vested interests would be intensely interested in finding a fix for the mandate, so you wouldn’t need a similarly liberal legislative coalition. I’d buy a conservatives-should-be-careful-what-they-wish-for in that case, but not if the whole ACA is struck down.
*UPDATE: Atrios is not, in fact, optimistic.