What about state-imposed individual mandates?

If the Supreme Court strikes down the individual mandate but leaves the rest of the ACA intact, one fact to keep in mind is that states maintain the right to impose such a mandate.  Backhandedly, even the plaintiffs acknowledged as much. The state respondents' brief makes much of a distinction between regulating commerce and "creating" it by requiring individuals to purchase something, asserting that Congress does not have the right to "compel individuals to engage in commerce." But the states do have that power:

The power to force individuals to engage in commercial transactions against their will was the kind of they reserved to state governments more directly accountable to the people (p. 17).*

Massachusetts, ICYMI, has exercised that power.  No one has challenged it.  And Mitt Romney has been insisting for two years that each state should have the power to find its own healthcare solution.

If the Court strikes down the mandate but leaves all other ACA regulations intact -- or even if it strikes down the general issue and community rating requirements that the mandate is designed to render economically feasible -- states will still be charged with establishing subsidized insurance exchanges.  There is virtual consensus among healthcare economists that the mandate is the key to making such private exchanges viable.  Will not states with Democratic governors and legislatures, while establishing exchanges, pass mandates of their own?

Perhaps not. A ruling striking down the mandate will put a stigma on it. Republicans' relentless demagoguery on the subject -- reversing their two decades of support for mandates -- has poisoned the well.  But on the other side of the ledger, the law in Massachusetts is popular. And working.

Question for Mitt Romney: if the mandate alone is struck, would you recommend that other states adopt mandates of their own?

* Verrilli highlighted this assertion of states' rights in his reply brief (p. 18), further arguing that the " authority of the federal government over interstate commerce does not differ in extent or character from that retained by the states over intrastate commerce" (p. 12). My discussion here.