Article VI, Clause 2:
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, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding.
Although the Supreme Court had held, prior to Chief Justice John Marshall’s appointment to it, that the Supremacy Clause rendered null and void a state constitutional or statutory provision that was inconsistent with a treaty executed by the Federal Government,1 it was left for Marshall to develop the full significance of the clause as applied to acts of Congress. By his vigorous opinions in McCulloch v. Maryland 2 and Gibbons v. Ogden ,3 Marshall gave the principle a vitality that survived a century of vacillation under the doctrine of dual federalism. In the former case, he asserted broadly that
the states have no power, by taxation or otherwise, to retard, impede, burden, or in any manner control, the operations of the constitutional laws enacted by Congress to carry into execution the powers vested in the general government. This is, we think, the unavoidable consequence of that supremacy which the constitution has declared.4 From this he concluded that a state tax upon notes issued by a branch of the Bank of the United States was void.
In Gibbons v. Ogden , the Court held that certain New York statutes that granted an exclusive right to use steam navigation on the waters of the state were null and void insofar as they applied to vessels licensed by the United States to engage in coastal trade. Chief Justice Marshall wrote:
In argument, however, it has been contended, that if a law passed by a state, in the exercise of its acknowledged sovereignty, comes into conflict with a law passed by Congress in pursuance of the constitution, they affect the subject, and each other, like equal opposing powers. But the framers of our constitution foresaw this state of things, and provided for it, by declaring the supremacy not only of itself, but of the laws made in pursuance of it. The nullity of an act, inconsistent with the constitution, is produced by the declaration, that the constitution is the supreme law. The appropriate application of that part of the clause which confers the same supremacy on laws and treaties, is to such acts of the state legislatures as do not transcend their powers, but though enacted in the execution of acknowledged state powers, interfere with, or are contrary to, the laws of congress, made in pursuance of the constitution, or some treaty made under the authority of the United States. In every such case, the act of congress, or the treaty, is supreme; and the law of the state, though enacted in the exercise of powers not controverted, must yield to it.5