Commerce Clause

The Commerce Clause in Article I, Section 8 of the Constitution grants Congress the power "to regulate Commerce... among the several States." It has become the single most important source of federal regulatory power and has been the subject of ongoing debate about the balance between federal and state authority.

The scope of congressional commerce power has expanded dramatically since the founding. Gibbons v. Ogden (1824) established a broad reading of "commerce among the states." The New Deal era saw the most significant expansion, with Wickard v. Filburn (1942) holding that Congress could regulate even purely local activities that, in the aggregate, substantially affect interstate commerce.

The modern framework recognizes three categories of activity Congress may regulate under the Commerce Clause: (1) the channels of interstate commerce (highways, waterways, internet); (2) the instrumentalities of interstate commerce and persons or things in interstate commerce (trucks, planes, goods); and (3) activities that substantially affect interstate commerce. The third category has been the most contested.

United States v. Lopez (1995) marked the first time in sixty years that the Court struck down a federal statute as exceeding Commerce Clause power, holding that gun possession near schools was not economic activity substantially affecting commerce. NFIB v. Sebelius (2012) reinforced limits by holding that the individual mandate could not be sustained under the Commerce Clause because Congress cannot compel individuals to engage in commerce.

The dormant commerce clause — a negative implication of the Commerce Clause — prohibits states from discriminating against or unduly burdening interstate commerce even in the absence of federal legislation.