The slim support that the Constitution has in the Supreme Court will be on open display in the weeks ahead during the court’s evaluation of ObamaCare’s insurance mandate. In one of its most important 5–4 decisions, the court held in United States v. Lopez (1995) that the federal government’s power to regulate interstate commerce had at least some limit. The court struck down the Gun Free School Zones Act, a federal law banning possession of a gun within 1,000 feet of a school. Not only did nearly every state have a similar law, but possessing a gun in a particular location is neither commercial activity nor (as the Supreme Court had already embellished the clause) does it substantially affect commerce. Justice Breyer’s dissent insisted, in effect, that interstate commerce is whatever the federal government says it is. In other words, four justices believed that the federal government can essentially define its own powers.

