It’s already been declared constitutional. That battle has been fought and lost. There is no Supreme Supreme Court to go to. The next battle is to get it repealed. That battle will take place in the House and Senate. So it is going to be easier to get it repealed if it only takes 51 votes than if takes 60 votes. The math is real simple for everyone except apparently Romney’s spokesman and some of his supporters on FR.
Mittens agrees it’s penalty that is unconstitutional.
That doesn’t mean he won’t support a bill to overturn it if it’s done on reconciliation.