What is the Supremacy Clause?
Supremacy Clause
The Supremacy Clause of the United States Constitution (Article VI, Clause 2) establishes that the Constitution, federal laws made pursuant to it, and treaties made under its authority, constitute the supreme law of the land.[1] It provides that state courts are bound by the supreme law; in case of conflict between federal and state law, the federal law must be applied. Even state constitutions are subordinate to federal law.[2] In essence, it is a conflict-of-laws rule specifying that certain federal acts take priority over any state acts that conflict with federal law. In this respect, the Supremacy Clause follows the lead of Article XIII of the Articles of Confederation, which provided that "Every State shall abide by the determination of the United States in Congress Assembled, on all questions which by this confederation are submitted to them."[3] A constitutional provision announcing the supremacy of federal law, the Supremacy Clause assumes the underlying priority of federal authority, at least when that authority is expressed in the Constitution itself.[4] No matter what the federal government or the states might wish to do, they have to stay within the boundaries of the Constitution. This makes the Supremacy Clause the cornerstone of the whole American political structure.[5][6]
Rice v. Santa Fe Elevator Corp.
Conclusion: The test, therefore, is whether the matter on which the State assets the right to act is in any way regulated by the Federal Act. If it is, the federal scheme prevails though it is a more modest, less pervasive regulatory plan than that of the State. By that test each of the nine matters we have listed is beyond the reach of the Illinois Commission since on each one Congress has declared its policy in the Warehouse Act. The provisions of Illinois law on those subjects must therefore give way by virtue of the Supremacy Clause. U.S.Const., Art. VI, Cl. 2.