Editors' Summary: In United States v. Lopez, the U.S. Supreme Court for the first time in 62 years struck down a federal statute on grounds that it violated the Commerce Clause of the U.S. Constitution. The Gun-Free School Zones Act of 1990 was unconstitutional because it intruded into an area of traditional state concern and did not regulate a commercial activity, either directly or as part of a pervasive regulatory scheme. Although United States v. Lopez involved only a discreet, isolated federal statute, the case may well have significant reverberations throughout all areas of federal law, including environmental law. The author examines in detail the majority, concurring, and dissenting opinions in the case, and then analyzes how the case is likely to affect federal environmental legislation. He concludes that while United States v. Lopez may signal judicial readiness to apply stricter scrutiny to federal legislation, most federal environmental laws — with their close ties to commerce — should still survive constitutional challenges.