GMAS US History EOC Practice Test 2026 – Full Exam Prep Resource

The main idea here is how the Commerce Clause power of Congress can be limited and how that ties into the balance between national and state authority. United States v. Lopez (1995) is the key case because it held that possessing a gun in a local school zone is not an activity that substantially affects interstate commerce, so Congress exceeded its constitutional power when it passed the Gun-Free School Zones Act.

This ruling narrowed the reach of the Commerce Clause by insisting on a substantial connection to interstate commerce for federal regulation. It signaled a shift toward reasserting states’ police powers and limiting federal reach in areas not clearly tied to economic activity that has a broad, interstate impact.

By contrast, the other cases involve different aspects of federal power: McCulloch v. Maryland and Gibbons v. Ogden broadly supported federal authority over commerce and implied powers, while Dred Scott v. Sandford dealt with citizenship and slavery and isn’t about regulating commerce at all.