The Supreme Court begins hearing oral arguments on the constitutionality of Obamacare Monday—the ruling that results will be the most significant decision any of the nine justices will ever render, and that includes the one that decided the 2000 presidential election.

The justices are charged solely with ruling on whether the law meets constitutional standards. But it doesn’t hurt that the law is enormously unpopular with the public and that it is recognized as “a big, disastrous deal,” as the headline on a Washington Times piece by Dr. Milton Wolf puts it.

The Galen Institute reports that, far from making medical care more accessible and less expensive, the Affordable Care Act is driving up the costs.  

 More is at stake than these practical issues, however, as important as they are. If the Court upholds the Affordable Care Act, then individual rights vis a vis the federal government will have diminished.

In a must-read, if somewhat complicated,  piece in this morning’s Wall Street Journal,David B. Rivkin and Lee A. Casey, former Justice Department officials and lawyers for the 26 states challenging the constitutionality of the Affordable Care Act, lay out just how important this is:

At stake are the Constitution's structural guarantees of individual liberty, which limit governmental power and ensure political accountability by dividing that power between federal and state authorities. Upholding ObamaCare would destroy this dual-sovereignty system, the most distinctive feature of American constitutionalism. …

The administration originally based its right to require that citizens purchase a product, health insurance, on the Commerce Clause, but in recent weeks has been emphasizing the Necessary and Proper argument. Rivkin and Casey say neither works:

Congress has crossed a fundamental constitutional line. Neither the fact that every individual has some discernible impact on the economy, nor that virtually everyone will at some point in time use health-care services, is a sufficient basis for federal regulation.

Both of these arguments, advanced by ObamaCare's defenders, are flawed because they admit no judicially enforceable limiting principle marking the outer bounds of federal authority.

This, even more than cost, is what matters.