The United States Supreme Court held that the Gun-Free School Zones Act of 1990 exceeded Congress' power under the Commerce Clause because the Act sought to regulate a non-economic, intrastate activity.
United States v. Lopez, 115 S. Ct. 1624 (1995).
John W. Boyle,
Constitutional Law - Commerce Clause - Regulation by Congress,
Duq. L. Rev.
Available at: https://dsc.duq.edu/dlr/vol34/iss1/10