In the 1995 case United States v. Lopez, the Supreme Court ruled that Congress had exceeded its power to regulate interstate commerce by making it a felony to possess a gun within 1,000 feet of a primary or secondary school. Congress responded by amending the Gun-Free School Zones Act so that it applied only to "a firearm that has moved in or that otherwise affects interstate or foreign commerce."
Although nothing of substance had changed, federal appeals courts deemed that supposed limitation sufficient to address the Supreme Court's concern about "convert[ing] congressional authority under the Commerce Clause to a general police power of the sort retained by the States." Congress, in short, initially forgot that it was supposed to be regulating "interstate or foreign commerce." But after the Supreme Court reminded it, the invocation of that phrase supposedly was enough to fix the law.
