United States v. Lopez

Majority reasoning

The Court, through Chief Justice Rehnquist, identified three categories of activity Congress may regulate under the Commerce Clause: channels of interstate commerce, instrumentalities of and things in interstate commerce, and activities that substantially affect interstate commerce. The gun law fit only the third category, but the statute was a criminal law with nothing to do with commerce or economic enterprise, was not part of a broader economic regulatory scheme, and contained no jurisdictional element requiring proof of a connection to interstate commerce. The majority rejected the government's argument that gun violence near schools raises insurance costs, deters travel, and harms the national economy through poorer education, reasoning that this logic would let Congress regulate virtually any activity, including family law and school curricula, eliminating the constitutional distinction between what is national and what is local. The Court noted Congress made no findings connecting the statute to commerce, though it said such findings are not always constitutionally required, and directly answered Justice Breyer's rationale that schools are "commercial" by pointing out that under his logic even child-rearing could be called commercial, showing the standard has no limiting principle.

Dissent reasoning

Justice Breyer, joined by Justices Stevens, Souter, and Ginsburg, argued that under decades of precedent Congress only needs a "rational basis" for concluding that a regulated activity, considered in the aggregate, significantly affects interstate commerce, and that Congress could rationally find that gun violence near schools undermines education, which in turn substantially harms the national economy given education's well-documented links to worker productivity and business location decisions. He contended the majority's commercial/noncommercial distinction is unworkable and inconsistent with cases like Perez, McClung, and Wickard, which did not turn on whether the underlying activity was itself commercial. Justice Stevens separately argued that guns are themselves articles of commerce and that Congress's power to regulate firearms includes the power to prohibit their possession in particular markets, including the substantial market for handguns among school-age children. Justice Souter argued that the majority's approach to grading judicial deference based on the "commercial" character of regulated conduct echoes the discredited pre-1937 direct/indirect effects test and Lochner-era substantive due process review, and that the Court has no better institutional basis for second-guessing Congress's economic judgments now than it did before 1937.