Ware v. Hylton, Excerpt of Opinion of Justice Samuel Chase:

It is admitted, that Virginia could not confiscate private debts without a violation of the modern law of nations, yet if in fact, she has so done, the law is obligatory on all the citizens of Virginia, and on her Courts of Justice; and, in my opinion, on all the Courts of the United States. If Virginia by such conduct violated the law of nations, she was answerable to Great Britain, and such injury could only be redressed in the treaty of peace. Before the establishment of the national government, British debts could only be sued for in the state court. This, alone, proves that the several states possessed a power over debts....

If doubts could exist before the establishment of the present national government, they must be entirely removed by the 6th article of the Constitution, which provides 'That 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.' There can be no limitation on the power of the people of the United States. By their authority the State Constitutions were made, and by their authority the Constitution of the United States was established; and they had the power to change or abolish the State Constitutions, or to make them yield to the general government, and to treaties made by their authority. A treaty cannot be the Supreme law of the land, that is of all the United States, if any act of a State Legislature can stand in its way. If the Constitution of a State (which is the fundamental law of the State, and paramount to its Legislature) must give way to a treaty, and fall before it; can it be questioned, whether the less power, an act of the State Legislature, must not be prostrate? It is the declared will of the people of the United States that every treaty made, by the authority of the United States, shall be superior to the Constitution and laws of any individual State; and their will alone is to decide. If a law of a State, contrary to a treaty, is not void, but voidable only by a repeal, or nullification by a State Legislature, this certain consequence follows, that the will of a small part of the United States may control or defeat the will of the whole. The people of America have been pleased to declare, that all treaties made before the establishment of the National Constitution, or laws of any of the States, contrary to a treaty, shall be disregarded.

Four things are apparent on a view of this 6th article of the National Constitution. 1st. That it is Retrospective, and is to be considered in the same light as if the Constitution had been established before the making of the treaty of 1783. 2nd. That the Constitution, or laws, of any of the States so far as either of them shall be found contrary to that treaty are by force of the said article, prostrated before the treaty. 3rd. That consequently the treaty of 1783 has superior power to the Legislature of any State, because no Legislature of any State has any kind of power over the Constitution, which was its creator. 4thly. That it is the declared duty of the State Judges to determine any Constitution, or laws of any State, contrary to that treaty (or any other) made under the authority of the United States, null and void. National or Federal Judges are bound by duty and oath to the same conduct.

3 Dallas 199 (1796)