To tax, to spend, to regulate.

Two very different visions of the national government underpin the ongoing battle over the Affordable Care Act̂ (ACA). President Obama and supporters of the ACA believe in the power of government to protect individuals through regulation and collective action.^ By contrast, the ACA's Republican and Tea Party opponents see expanded government as a fundamental threat to individual liberty and view the requirement that individuals purchase minimum health insurance (the so-called "individual mandate") as the. conscription of the healthy to subsidize the sick.̂ This conflict over the federal government's proper role is, of course, not new; it has played out repeatedly over our nation's past.* But rarely since the New Deal has it surfaced in such a distinctly constitutional guise with respect to economic legislation. Instead, after the Supreme Court sustained broad congressional power