Justice O’Connor joins the 5–4 majority in United States v. Lopez, limiting Congress’s Commerce Clause power over gun-free school zones.
On April 26, 1995, the Supreme Court issued its landmark decision in United States v. Lopez, with Justice Sandra Day O’Connor joining the 5–4 majority that struck down the Gun‑Free School Zones Act of 1990 as exceeding Congress’s power under the Commerce Clause.
The majority held that possession of a gun in a local school zone was not an economic activity that substantially affected interstate commerce, and therefore Congress lacked constitutional authority to criminalize it under the Commerce Clause. O’Connor’s vote was pivotal in a ruling that marked the first time in decades the Court had invalidated a federal statute on Commerce Clause grounds, signaling a renewed enforcement of limits on federal power.
Historically, Lopez is seen as a turning point in constitutional law, inaugurated a line of cases scrutinizing federal regulatory authority and reinforcing the role of the states. O’Connor, often a swing vote, aligned with a vision of federalism that preserved meaningful spheres of state sovereignty.
For women’s history, her participation underscores the influence that women justices wielded in major structural constitutional decisions—not only in cases involving gender equality but in the foundational allocation of power between federal and state governments.