When state law and federal law collide, who wins? One short clause in the Constitution answers that question, and it answers it the same way every time.
The Supremacy Clause, in Article VI, declares that the Constitution and the federal laws and treaties made under it are the supreme law of the land. When a valid federal law conflicts with a state law, the federal law prevails.
It solved a fatal flaw in the first American government. Under the Articles of Confederation, the states could ignore national decisions almost at will, leaving the central government toothless. The Supremacy Clause made federal law actually binding on the states.
It does not make the federal government all-powerful. Federal law is supreme only when it is constitutional and within the powers granted to it. A federal act that exceeds those powers is not supreme; it is void.
Judges are bound by it directly. The clause says judges in every state shall be bound by the supreme law, even against their own state's constitution, which is what lets federal courts strike down conflicting state laws.
