I thought that the Supreme Court wasn't allowed to rule on whether a tax is constitutional until it takes effect? If the mandate is a tax than shouldn't the suit have been dismissed and need to be reargued in a couple years?
Ah, there is a distinction (the reasoning isn't mine, of course - I am not clever enough). The constitutionality is decided based on what this truly is, ignoring the labeling the Congress chooses to provide - a tax. But the prohibition on ruling pro/contra constitutionality of taxes not yet in effect is based on a statute and the Congress can choose to word the statute as it likes. It prohibited ruling on constitutionality not of taxes, but only of things it chooses to call taxes. Hence, this is a tax for the purposes of a constitutional argument, but not a tax for the purposes of this particular statute