Definition
The Commerce Clause is the provision in Article I that empowers Congress to regulate commerce with foreign nations, among the several states, and with Native American tribes. It is one of the most consequential grants of authority in the entire Constitution.
Because so much of modern economic life crosses state lines, the clause has become the basis for a wide range of federal laws, from civil rights statutes to environmental and workplace regulation.
Why it matters
How it works
Congress invokes the clause to address activity that affects interstate commerce, even when an individual transaction seems local. Courts have at various times read the clause broadly, allowing extensive federal regulation, and more narrowly, insisting on a genuine link to interstate activity.
A related principle, sometimes called the dormant Commerce Clause, limits states from discriminating against or unduly burdening interstate trade even when Congress has not acted. Together these strands keep the national market open.