Interstate commerce

The Commerce Clause describes an enumerated power listed in the United States Constitution (Article I, Section 8, Clause 3). The clause states that the United States Congress shall have power "To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes." Courts and commentators have tended to discuss each of these three areas of commerce as a separate power granted to Congress. It is common to see the individual components of the Commerce Clause referred to under specific terms: The Foreign Commerce Clause, the Interstate Commerce Clause, and the Indian Commerce Clause.

Dispute exists within the courts as to the range of powers granted to Congress by the Commerce Clause. As noted below, the clause is often paired with the Necessary and Proper Clause, the combination used to take a broad, expansive perspective of these powers. However, the effect of the Commerce Clause has varied significantly depending on the Supreme Court's interpretation. During the Marshall Court era, Commerce Clause interpretation empowered Congress to gain jurisdiction over numerous aspects of intrastate and interstate commerce as well as non-commerce. During the post-1937 era, the use of the Commerce Clause by Congress to authorize federal control of economic matters became effectively unlimited. Since the latter half of the Rehnquist Court era, Congressional use of the Commerce Clause has become slightly restricted again, being limited only to matters of trade or any other form of restricted area (whether interstate or not) and production (whether commercial or not).

The Commerce Clause is the source of federal drug prohibition laws under the Controlled Substances Act. In the recent medical marijuana case, Gonzales v. Raich, the Supreme Court rejected the argument that the ban on growing medical marijuana for personal use exceeded Congress' powers under the Commerce Clause. Even if no goods were sold or transported across state lines, the Court found that there could be an "indirect" effect on interstate commerce. In reaching this conclusion, the Court relied heavily on the New Deal era case, Wickard v. Filburn, which held that the government may regulate personal cultivation and consumption of crops because the aggregate effect of individual consumption could have an "indirect" effect on interstate commerce.

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