Supremacy Clause

The Supremacy Clause, found in Article VI, Clause 2 of the Constitution, establishes that the Constitution, federal statutes enacted pursuant to it, and treaties made under the authority of the United States are the supreme law of the land. Judges in every state are bound by this principle, and state constitutions and laws must yield to valid federal authority when the two conflict.

Federal preemption is the primary doctrinal vehicle through which the Supremacy Clause operates. Preemption comes in several forms: express preemption, where Congress explicitly states its intent to displace state law; field preemption, where federal regulation is so pervasive that Congress is deemed to have occupied the entire regulatory field; and conflict preemption, which arises when compliance with both federal and state law is physically impossible or where state law stands as an obstacle to the accomplishment and execution of federal purposes.

The Supremacy Clause is not an independent grant of federal power; rather, it establishes a rule of priority. Federal law must itself be valid under the Constitution before it can preempt state law. Courts apply a presumption against preemption in areas of traditional state authority, requiring a clear and manifest purpose of Congress to supersede state law. This presumption reflects federalism values and ensures that the federal-state balance is not inadvertently upset. The Supremacy Clause is thus a structural provision that ensures the coherence and uniformity of the federal legal system.