The argument against the individual mandate—the requirement that everyone buy health insurance or pay a penalty—is carefully anchored in constitutional precedent and American history. The Commerce Clause that the government invokes to defend such regulation has always applied to commercial and economic transactions, not to individuals as members of society.

This distinction is crucial. The health-care and health-insurance markets are classic interstate commerce. The federal government can regulate broadly—though not without limit—and it has. It could even mandate that people use insurance to purchase the services of doctors and hospitals, because then it would be regulating market participation. But with ObamaCare the government is asserting for the first time that it can compel people to enter those markets, and only then to regulate how they consume health care and health insurance. In a word, the government is claiming it can create commerce so it has something to regulate.

This is another way of describing plenary police powers—regulations of private behavior to advance public order and welfare. The problem is that with two explicit exceptions (military conscription and jury duty) the Constitution withholds such power from a central government and vests that authority in the states. It is a black-letter axiom: Congress and the President can make rules for actions and objects; states can make rules for citizens.