When Obamacare has run into difficulties before, its proponents have tried to blame those difficulties on Republican sabotage. The program would be working better, they have said, if Republicans had set up exchanges in the states or expanded Medicaid. None of that seemed to work beyond the liberal base. Maybe it wouldn’t work this time either.

I would also take with a grain of salt the prediction that in a post-Halbig world states will all rush to adopt exchanges to keep the tax credits flowing. Maybe they will. But there will be a strong other side of the argument: that putting exchanges in place will trigger the employer mandate and, for many people, the individual mandate too.

Of course all of this is conditional on the result in Halbig holding up, which may not happen.