Unfortunately, the Constitution says whatever 5 out of 9 Supreme Court Justices say it says.
So far, two Clinton appointed federal judges have ruled that Obamacare is constitutional and two Republican appointed Judges (one Bush appointee and one Reagan appointee) have held that it is unconstitutional.
Ultimately, the issue is going to be decided whichever way Anthony Kennedy decides to vote on the Supreme Court.
Related?
The only thing that will be debatable will be if the whole thing must be thrown out (which it must in my opinion) or whether the mandate can be severed from the rest.
The reason the mandate CAN NOT be severed from the rest... simply everyone would drop their insurance tomorrow ... and wait till they got sick or hurt then buy insurance the insurance companies are required to sell by law.