Which case is a landmark example of Congress regulating local activity because of its substantial effect on interstate commerce?

• A. Gibbons v. Ogden (1824)
• B. Wickard v. Filburn (1942)
• C. United States v. Lopez (1995)
• D. Heart of Atlanta Motel v. United States (1964)

Answer: (B)

The key idea is how Congress can regulate activities under the Commerce Clause when those activities, taken together, have a substantial effect on interstate commerce, even if each activity is local or seemingly minor. Wickard v. Filburn is the landmark example of this. The Court held that a farmer growing wheat for personal use could be regulated because, when all farmers’ similar local production is combined, it could influence national wheat prices and supply. The decision uses an aggregation principle: individual local activity can be regulated if its cumulative impact on the economy is substantial enough to affect interstate commerce. This set a broad standard for congressional power under the Commerce Clause for years.

Gibbons v. Ogden is about establishing the federal government’s power to regulate interstate commerce in general, not the specific aggregation rationale. United States v. Lopez, by contrast, limits Commerce Clause power by ruling that non-economic activities like carrying a gun in a school zone don’t have a substantial enough effect on interstate commerce. Heart of Atlanta Motel v. United States involves regulating local business under the Civil Rights Act on commerce grounds, which is related but not the quintessential illustration of the aggregation principle Wickard formalizes.