I think Jamelle's post below perfectly captures the flavor of last night's GOP debate, in which what was generally a contest to see who could be more wingnutty was occasionally interrupted by a candidate put on the defensive because they had done or said something reasonable. I'm not surprised, given this, that one challenge Michele Bachmann made to Mitt Romney has gotten less attention. Bachmann asserted not only that Romney couldn't be trusted to repeal the ACA but that the Massachusetts health bill he signed was unconstitutional: "No state has the constitutional right to force a person as a condition of citizenship to buy a product or service against their will. It's unconstitutional." She has made similar claims before.
Officially, Bachmann is going off the reservation when she says that Romney's health-care bill is unconstitutional. Legal challenges to to the Affordable Care Act have generally argued that the bill exceeds Congress's powers under the Commerce Clause, an argument that wouldn't apply to state governments. And, yet, I think she's onto something.
Essentially, judges who who have ruled the ACA unconstitutional have used arguments that would apply just as much to a state mandate as a federal one. The federalist arguments that focus on the commerce clause have always seemed to me like window dressing to justify an intuitive libertarian opposition to the mandate. One could argue that the litigation campaign against the ACA in large measure actually reflects the now-discredited "liberty of contract" doctrines of the early 20th century, which held that regulations such as minimum-wage and maximum-hours laws violated the 14th Amendment. Bachmann isn't explicitly naming Lochner v. New York, the 1905 case which symbolizes the liberty of contract doctrine that was sometimes used to strike down progressive legislation until the New Deal, but it's unlikely she is touting the idea that the individual mandate violates the Constitution no matter which level of government enacts it without Lochner in mind. And the fact that one of the top three candidates for the Republican nomination is willing to call for a return to the Lochner era -- something many on the far-right/libertarians side of the spectrum only dream of -- is news in itself.