---
title: "United States v. Lopez — Definition & Meaning"
description: "United States v. Lopez (1995) is a key Supreme Court case that limited Congress's Commerce Clause power, impacting federal authority over states."
url: "https://modeldiplomat.com/learn/glossary/united-states-v-lopez"
---

[New](https://modeldiplomat.com/)

#

Model Diplomat Research Team · Last reviewed June 22, 2026

TL;DR

- United States v.
- Lopez (1995) is the Supreme Court decision that struck down a federal statute as exceeding Congress's Commerce Clause power for the first time since 1937.
- Why is United States v. Lopez historically significant?
- What three categories of regulable activity did the Court identify?
- How does Lopez relate to Morrison and Raich?

[Civil Service & Diplomatic Exams](https://modeldiplomat.com/learn/civil-services/glossary)Updated June 22, 2026

Go beyond the definition

## Research United States v. Lopez like a delegate

Model Diplomat's AI drafts position papers, speeches, and country research with real sources — built for MUN and politics students.

## Research it like a delegate

Research on modeldiplomat.com

## Ask a follow-up about United States v. Lopez

Open a cited briefing in Model Diplomat search — timelines, positions, and sources you can use in committee or exam answers.

[Start research on United States v. Lopez](https://modeldiplomat.com/search?q=Explain%20United%20States%20v.%20Lopez%20%E2%80%94%20key%20dates%2C%20actors%2C%20positions%2C%20and%20sources)

Example

In 1995 the Supreme Court, led by Chief Justice Rehnquist, struck down the Gun-Free School Zones Act after Texas student Alfonso Lopez Jr. was convicted for carrying a handgun to his San Antonio high school.

Keep learning

## Go deeper than the definition

Lessons

[Federalism Intergovernmental Relations](https://modeldiplomat.com/learn/lessons/fsot-us-government-federalism-intergovernmental-relations)[Landmark Supreme Court Cases Every Fso Should Know](https://modeldiplomat.com/learn/lessons/fsot-us-government-landmark-supreme-court-cases-every-fso-should-know)

Courses

[Fsot Us Government](https://modeldiplomat.com/learn/courses/fsot-us-government)

[Explore all Civil Service & Diplomatic Exams lessons](https://modeldiplomat.com/learn/civil-services)[Test yourself with a quiz](https://modeldiplomat.com/learn/glossary/quiz/civil-services)

## Take United States v. Lopez beyond the glossary

Ask the AI research engine built for diplomacy — get briefings, position papers, and speeches with sources you can cite in committee.