The Brady law, which imposes a five-day waiting period for gun purchases and requires state officials to conduct background checks of purchasers, has already been declared unconstitutional in a half-dozen Federal district courts. The basis for those decisions, which the Clinton Administration is appealing, was not the Congressional commerce power but state autonomy under the 10th Amendment, which reserves to the states the powers not explicitly delegated to the Federal Government by the Constitution.

While that is a different rationale than the one the Court employed today, the 10th Amendment and the commerce clause are closely related elements of an ongoing constitutional debate over state power within the Federal system.

The language of federalism rang strongly through Chief Justice Rehnquist's majority opinion, as well as in a concurring opinion filed by Justices Anthony M. Kennedy and Sandra Day O'Connor. Justices Antonin Scalia and Clarence Thomas, who filed his own concurring opinion, were the other members of the majority.

Joining Justice Breyer in dissenting were Justices John Paul Stevens, David H. Souter and Ruth Bader Ginsburg. Justice Breyer took the unusual step of reading from the bench this morning a portion of the dissenting opinion he wrote for himself and the three others. Justices Stevens and Souter filed their own dissenting opinions as well. Justice Stevens called the majority ruling "extraordinary."

In his majority opinion, Chief Justice Rehnquist said the Administration's arguments for upholding the Gun-Free School Zones Act "would bid fair to convert Congressional authority under the commerce clause to a general police power of the sort retained by the states."

The Chief Justice said the law was "a criminal statute that by its terms has nothing to do with 'commerce' or any sort of economic enterprise, however broadly one might define those terms." He rejected the Administration's argument that guns and violence in schools hurt the economy by undermining the educational process and making children less productive workers and citizens.

"If we were to accept the Government's arguments, we are hard-pressed to posit any activity by an individual that Congress is without power to regulate," Chief Justice Rehnquist said. By the same logic, he added, school curriculums and state laws governing divorce and child custody would also come under Federal control.