United States v. Lopez (1995) is a required AP Gov Supreme Court case in which the Court struck down the Gun-Free School Zones Act, ruling that carrying a gun in a school zone is not interstate commerce, which limited Congress's Commerce Clause power for the first time in decades and shifted power back toward the states.
United States v. Lopez (1995) is one of the required Supreme Court cases for AP Gov, and it lives in Topic 1.8, Constitutional Interpretations of Federalism. Alfonso Lopez was a high school senior in San Antonio who brought a concealed handgun to school. The federal government charged him under the Gun-Free School Zones Act of 1990, a law Congress passed using its Commerce Clause power. The Supreme Court said no. Carrying a gun near a school is not economic activity, and it is not interstate commerce, so Congress had no constitutional authority to regulate it. Gun possession in schools is a matter for state law.
Why is that a big deal? For about 60 years before Lopez, the Court had let Congress stretch the Commerce Clause to cover almost anything (think Wickard v. Filburn, where even wheat grown for personal use counted as interstate commerce). Lopez was the first time since the New Deal era that the Court told Congress it had gone too far. The decision did not delete the Commerce Clause, but it drew a line. Congress's enumerated powers have limits, and the Tenth Amendment reserves the rest to the states.
Lopez is the textbook example for learning objective AP Gov 1.8.A, which asks you to explain how the balance of power between national and state governments has shifted over time based on Supreme Court interpretations. The essential knowledge for 1.8 says it directly: the Commerce Clause gives the national government power to regulate interstate commerce, but Supreme Court interpretations control how far that power reaches. Lopez is the case that shows the pendulum swinging back toward the states. Paired with McCulloch v. Maryland (which expanded federal power), it gives you both directions of the federalism story in Unit 1. If an exam question asks for evidence that federal power is limited, Lopez is your go-to.
Keep studying AP Gov Unit 1
Commerce Clause (Unit 1)
Lopez only makes sense as a Commerce Clause case. Congress justified the Gun-Free School Zones Act under its power to regulate interstate commerce, and the Court rejected that justification because gun possession in a school zone is not commerce at all. Lopez is the case you cite to show the Commerce Clause has a ceiling.
Wickard v. Filburn (Unit 1)
Wickard (1942) is the high-water mark of the broad Commerce Clause, where wheat a farmer grew for himself still counted as interstate commerce. Lopez is the course correction. Put them together and you have a clean before-and-after timeline of how the Court's reading of one clause expanded and then contracted federal power.
Federalism (Unit 1)
Lopez is federalism in action. The ruling protected the states' traditional police powers (like regulating schools and criminal law) from federal takeover. It is concrete evidence that federalism is not just a founding-era idea but a live constitutional limit the Court still enforces.
Enumerated Powers (Unit 1)
The core logic of Lopez is that Congress only has the powers listed in Article I. If a federal law cannot be tied to an enumerated power like regulating interstate commerce, it is unconstitutional. Lopez proves the enumerated powers doctrine has real teeth.
Lopez is one of the 15 required Supreme Court cases, so the College Board expects you to know the facts, the constitutional clause at issue, the holding, and the reasoning. Multiple-choice questions often ask which required case limited Congress's Commerce Clause power by striking down the Gun-Free School Zones Act (that's Lopez, every time). The bigger payoff is the SCOTUS Comparison question. The 2024 exam gave a stimulus on Katzenbach v. McClung (1964), a case that upheld the Civil Rights Act under the Commerce Clause, and asked how it compared to Lopez. That pairing is the classic move: a non-required case where the Commerce Clause argument won versus Lopez, where it lost. To score, you need to identify the Commerce Clause as the shared constitutional provision, then explain why the Court reached opposite outcomes (a restaurant serving interstate travelers and food is economic activity; a kid carrying a gun near a school is not).
Both are required federalism cases in Topic 1.8, but they pull in opposite directions. McCulloch (1819) expanded national power by reading the Necessary and Proper Clause broadly and blocking states from taxing the national bank. Lopez (1995) limited national power by reading the Commerce Clause narrowly. Quick check: McCulloch = Necessary and Proper Clause, federal power grows. Lopez = Commerce Clause, federal power shrinks. If an FRQ asks how Court interpretations shifted the federal-state balance over time, these two cases are the bookends.
United States v. Lopez (1995) struck down the Gun-Free School Zones Act because possessing a gun near a school is not interstate commerce.
It was the first time since the New Deal era that the Supreme Court limited Congress's Commerce Clause power, shifting authority back toward the states.
Lopez is a required case for learning objective AP Gov 1.8.A, showing that Supreme Court interpretation changes the federal-state balance of power.
Pair Lopez with McCulloch v. Maryland to argue both directions: McCulloch expanded federal power, Lopez restricted it.
On the SCOTUS Comparison FRQ, the Commerce Clause is the link between Lopez and cases like Katzenbach v. McClung, where the same clause produced the opposite result because the regulated activity was genuinely economic.
In 1995 the Supreme Court ruled that the Gun-Free School Zones Act of 1990 was unconstitutional because Congress's Commerce Clause power does not cover gun possession near schools, which is not economic activity. It was the first major limit on the Commerce Clause in roughly 60 years.
No. Congress can still regulate genuinely economic activity that affects interstate commerce, which is why laws like the Civil Rights Act of 1964 (upheld in Katzenbach v. McClung) remain valid. Lopez just established that the Commerce Clause has limits and cannot reach non-economic activity like carrying a gun in a school zone.
McCulloch (1819) expanded federal power using the Necessary and Proper Clause, while Lopez (1995) limited federal power by narrowing the Commerce Clause. They are the two required federalism cases in Topic 1.8 and represent opposite shifts in the federal-state balance.
It is the clearest modern example of the Supreme Court limiting national power and protecting state authority, which is exactly what learning objective AP Gov 1.8.A asks you to explain. It also shows up regularly in the SCOTUS Comparison FRQ, including the 2024 exam's pairing with Katzenbach v. McClung.
No, and this is a common trap. Lopez is a federalism case about the Commerce Clause, not a Second Amendment case. The required Second Amendment case is McDonald v. Chicago. Lopez asked whether Congress had the power to pass the law at all, not whether individuals have a right to carry guns.
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