Doesn't matter. I do not expect the Supremes to rule anything the government wants to do as unconstitutional. Obeying the Constitution is predicated on the fact that Congress can do anything as long as it is called a tax.
I don't know if they have to.
I've heard talk recently on FR that that is exactly why Roberts did what he did, and that he could foresee CA-RATs and other RAT-voters whacking-out about the high premiums and no benefits...can't find a doctor etc.
(Nyuck nyuck nyuck!)