The Supremacy Clause is located in Article VI, Clause 2 of the Constitution and reads: "This Constitution, and the laws of the United States which shall be made in pursuance thereof; and all treaties made, or which shall be made, under the authority of the United States, shall be the supreme law of the land; and the judges in every state shall be bound thereby, anything in the Constitution or laws of any State to the contrary notwithstanding." This clause solved a critical problem under the Articles of Confederation: there was no mechanism to ensure federal law superseded conflicting state law.
The Supremacy Clause establishes three tiers of law. The Constitution sits at the top. Below that are federal laws enacted by Congress pursuant to the Constitution's enumerated powers. Treaties made under federal authority rank similarly. State constitutions, state laws, and local ordinances occupy a lower tier—they're supreme within their domain only if they don't conflict with the Constitution or valid federal law. This hierarchy applies regardless of when laws were enacted; an older state law is preempted if it conflicts with newer federal law, and vice versa.
The Supremacy Clause's real-world effect depends on whether Congress actually exercised enumerated power. If Congress acts within its constitutional authority, its law automatically preempts conflicting state law. If Congress exceeds its enumerated powers, a court will strike the federal law down, and the state law may survive. This creates ongoing disputes about which government can regulate particular conduct—whether a matter falls within federal enumerated powers or within reserved state powers.
The Supremacy Clause ensures that federal law binds state officials and prevents states from creating a patchwork of conflicting rules on matters Congress validly regulates. It's the constitutional foundation for federal authority over interstate commerce, immigration, and other matters.
People often think the Supremacy Clause gives Congress unlimited power. In practice, Congress can only preempt state law by exercising its enumerated powers—if Congress exceeds those powers, its law is unconstitutional and doesn't preempt state law.
The Supremacy Clause ensures that federal law binds state officials and prevents states from creating a patchwork of conflicting rules on matters Congress validly regulates. It's the constitutional foundation for federal authority over interstate commerce, immigration, and other matters.
People often think the Supremacy Clause gives Congress unlimited power. In practice, Congress can only preempt state law by exercising its enumerated powers—if Congress exceeds those powers, its law is unconstitutional and doesn't preempt state law.