With the bill passed, it's a good time to follow up my previous discussion about its constitutionality. There are two questions here: Is the bill unconstitutional under current law, and what will the Supreme Court do?
On the first question, I think the bill is plainly constitutional under current law, as Jack Balkin explains here and here. Several commenters on the previous post seemed not to understand that the individual mandate was not a direct mandate in the sense of a criminal law requiring everyone to purchase tax insurance but is instead a tax penalty for people who don't have health insurance. Even the former would probably be constitutional under the broad conception of federal powers recently re-affirmed in Raich, but the latter is an easy case. The federal government has the explicit power to levy taxes, and the tax in this case is clearly necessary to achieve the broader goals of the legislation, goals that are unquestionably a legitimate exercise of federal power.
Of course, the fact that the bill would seem to be constitutional under current case law doesn't end the discussion. Citing Bush v. Gore, Jon Chait remains unconvinced that the Roberts Court would uphold the legislation. I wouldn't say it's impossible -- for one thing, the Supreme Court can overrule its own precedents -- but like Orin Kerr and Sandy Levinson, I think it's extremely unlikely. One thing that should be noted about Bush v. Gore is that it was in many respects sui generis, which in a sense gave the Court more leeway. Bush v. Gore was certainly an appalling decision, but it was appalling not because it squarely contradicted precedent or constitutional text but because its argument defending an apparently partisan result was so internally incoherent and unprincipled. To overturn a much more settled body of law, with implications for many other statutes favored by both parties, would be a very different animal. And if Kennedy and Scalia had the appetite for such a revolution, it's pretty hard to account for their votes in Raich.
But let's say that Bush v. Gore vindicates the strongest form of legal realism and that we will soon see that Supreme Court justices are purely political actors. Would striking down the individual mandate ultimately advance conservative policy goals? Almost certainly not. On the one hand, it would be easy for Congress to get around the decision by simply structuring the tax differently and constitutionally, restoring the status quo. But what if Congress can't? In some ways, this would be worse for conservatives -- unless Congress was also willing to repeal very popular regulations (which even conservatives concede is a non-starter), the result will be the bankruptcy of insurance companies and a paved road to socialized insurance.
So not only do I think that the Supreme Court won't strike down the ACA because only the mandate is subject to an even remotely serious constitutional challenge but also because the effects of a judicial intervention are likely to be much less dire than one might expect. The ultimate outcome would likely be a policy as good or better than the new status quo, with the Democrats in a stronger political position -- and I think the justices know this too.