As advocates gear up for the first appellate argument in the ongoing Obamacare lawsuits — Tuesday in Richmond — today marks an important milestone: the filing of two eloquent briefs responding to the government’s appeal of Judge Roger Vinson’s January ruling that found the individual mandate unconstitutional and non-severable, thereby striking the entire legislation.

These two briefs, one by 26 states (and for the first time signed by former solicitor general Paul Clement) and one by the private co-plaintiffs in that same Florida case (the National Federation of Independent Business and two individuals) present a full-throated defense of the basic principle upon which this country was founded: that the federal government is one of enumerated and limited powers whose primary goal is to preserve liberty. They describe exhaustively why that government cannot require people to buy goods or services as a means of regulating interstate commerce and why therefore the unprecedented individual mandate goes beyond what the Constitution authorizes. Indeed, forcing people to buy health insurance is neither a regulation of interstate commerce nor a constitutionally appropriate means of achieving such regulation.

If the Eleventh Circuit, which will hear argument June 8 in Atlanta, takes these arguments seriously — and adheres to the truism that the Constitution provides fixed limits on federal power — then the “linchpin” of Obamacare is doomed. Any ruling to the contrary, allowing the individual mandate to stand, would unleash an entirely novel and unbounded conception of federal power.

Cato will be filing our own brief a week from today. Georgetown law professor and Cato senior fellow Randy Barnett will not be on it, however, because he has joined the NFIB’s legal team — an exciting development, to be sure!