things all the time.

Plus, the grounds on which they held it up was also unprecedented in that the Supremes have never been asked to rule on a tax on inactivity, nor has any such tax ever been enacted.

But I'm really not going to ever be convinced by the idea that something they do is unprecedented, because it's their bloody job to create precedents. The same goes for things where the law is "settled" by a previous Supreme Court decision, because if a Supreme Court ruling couldn't be undone by other Supreme Court rulings we'd still have separate water fountains.

At any rate, the main dissent in Sebelius was that the Commerce Clause did not allow Congress that kind of power. The Court certainly has exercised its jurisdiction more recently than the '20s to tell Congress not to use the Commerce Clause to enforce certain behavior. US attorneys failed in their arguments before the Rehnquist court to allow the Commerce Clause to justify various laws regarding gun control and domestic violence, and parts of these laws were in fact overturned.

So, to recap: Overturning Obamacare via the Commerce Clause would clearly not have been unprecedented, as several other laws have been struck down recently on that basis.