the supremacy clause of the constitution means that
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 national acts take priority over any state acts that conflict with national 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]
States' rights The balance of federal powers and those powers held by the states as defined in the Supremacy Clause of the U.S. Constitution was first addressed in the case of McCulloch v. Maryland (1819). The Court's decision by Chief Justice John Marshall asserted that the laws adopted by the federal government, when exercising its constitutional powers, are generally paramount over any conflicting laws adopted by state governments. After McCulloch, the primary legal issues in this area concerned the scope of Congress' constitutional powers, and whether the states possess certain powers to the exclusion of the federal government, even if the Constitution does not explicitly limit them to the states.[3][4]