Just keep in mind

No one would doubt the constitutionality of the mandate if it were done as a tax incentive instead of as a tax penalty. The government gives tax incentives for all kinds of things, like mortgage interest or college or hiring veterans. The heart of the conservative case is at best a technicality, as the exact same mandate, in real terms as they affect citizens, would certainly be constitutional. They're prepared to overrule the legislature (which supposed proponents of judicial restraint should be reluctant to do) on a major pies of legislation on a technicality.