Writing for Monday's majority, Justice John Paul Stevens, perhaps the most liberal justice, was joined by Justices Stephen Breyer, David Souter, Ruth Bader Ginsburg and Anthony Kennedy. Scalia concurred separately. Stevens said that one does not need ``a degree in economics to understand why a nationwide exemption'' for large quantities of marijuana cultivated for personal use could have a ``substantial impact on the interstate market'' for a commodity that Congress aims to ``conquer.'' Scalia, responding to the two women's and the court minority's invocation of states' sovereignty, cited a previous court ruling that Congress may regulate even when its regulation ``may pre-empt express state-law determinations contrary to the result which has commended itself to the collective wisdom of Congress.''
Justice Sandra Day O'Connor, a former Arizona state legislator, dissented, echoing Justice Louis Brandeis' judgment that federalism is supposed to allow a single state to be a ``laboratory'' to ``try novel social and economic experiments without risk to the rest of the country.'' Her dissent was joined by Chief Justice William Rehnquist, who wrote the court's opinion in a 1995 case that conservatives mistakenly hoped would signal substantial inhibitions on Congress in the name of federalism. In that case, the court overturned, as an invalid exercise of the power to regulate commerce, a federal law regulating the possession of guns near schools.
Thomas, the justice least respectful of precedents, joined O'Connor's dissent and also dissented separately, disregarding many precedents giving almost infinite elasticity to the Commerce Clause. He said that the women's marijuana was never bought or sold, never crossed state lines and had no ``demonstrable'' effect on the national market for marijuana: ``If Congress can regulate this under the Commerce Clause, then it can regulate virtually anything'' including ``quilting bees, clothes drives and potluck suppers.'' Thus ``the federal government is no longer one of limited and enumerated powers.'' But that has been the case at least since 1942.
In Monday's decision, which of the justices were liberal, which were conservative? Which exemplified judicial activism, which exemplified restraint? Such judgments are not as easy as many suppose.