Which landmark decision limited Congress's power under the Commerce Clause?

The landmark decision that limited Congress's power under the Commerce Clause is United States v. Lopez. This case, decided in 1995, marked a significant shift in the interpretation of the Commerce Clause, which had often been used to justify broad federal regulatory power over various aspects of economic and non-economic activities.

In United States v. Lopez, the Supreme Court struck down the Gun-Free School Zones Act of 1990, which prohibited the possession of firearms in school zones. The Court found that the law exceeded Congress's authority under the Commerce Clause because the possession of a gun in a school zone was not an economic activity that substantially affected interstate commerce. This ruling underscored a more limited view of the federal government's powers, emphasizing that while Congress has broad authority to regulate commerce, that authority is not unlimited and does not extend to every activity that may have a tangential effect on interstate commerce.

The decision highlighted a growing judicial willingness to assert limits on federal powers, reinforcing states' rights and marking a notable retreat from the expansive interpretation of congressional authority that had characterized earlier cases. Through this ruling, the Court established clear boundaries for Congress's use of the Commerce Clause, making it a pivotal moment in constitutional law and federalism.