The Supreme Court has established that it would require a successful rebellion.
Of course. What sort of government would it be, if a condition of joining was "Oh, if you don't like it here, you are welcome to leave when you decide to"?
The Feds get some of their power by limiting the options available to those they govern. Sometimes (as in states joining the Union) that can be a Good Thing(tm), other times (like mandated heath care with non-governmental agencies) it can be a Bad Thing(tm). It's a situational thing.
Meh... if you want to drive a car, you're mandated to purchase car insurance, and since no state offers a state-run car insurance system, it's forcing you to buy something from the private sector.
The argument from the right should never have been that it is a mandate policy, but rather their argument should be that it's outside of the bounds of the Federal government... each state still is allowed to establish the exact same mandates.
For instance, Massachusetts has a mandate to purchase healthcare as well, and it was pushed out by the right-winger Romney.