All questions of power, arising under the constitution of the United States, whether they relate to the federal or a state government, must be considered of great importance. The federal government being formed for certain purposes, is limited in its powers, and can in no case exercise authority where the power has not been delegated. The states are sovereign; with the exception of certain powers, which have been invested in the general government, and inhibited to the states. No state can coin money, emit bills of credit, pass ex post facto laws, or laws impairing the obligation of contracts, &c. If any state violate a provision of the constitution, or be charged with such violation to the injury of private rights, the question is made before this tribunal; to whom all such questions, under the constitution, of right belong. In such a case, this court is to the state, what its own supreme court would be, where the constitutionality of a law was questioned under the constitution of the state. And within the delegation of power, the decision of this court is as final and conclusive on the state, as would be the decision of its own court in the case stated.
That distinct sovereignties could exist under one government, emanating from the same people, was a phenomenon in the political world, which the wisest statesmen in Europe could not comprehend; and of its practicability many in our own country entertained the most serious doubts. Thus far the friends of liberty have had great cause of triumph in the success of the principles upon which our government rests. But all must admit that the purity and permanency of this system depend on its faithful administration. The states and the federal government have their respective orbits, within which each must revolve. If either cross the sphere of the other, the harmony of the system is destroyed, and its strength is impaired. It would be as gross usurpation on the part of the federal government, to interfere with state rights, by an exercise of powers not delegated; as it would be for a state to interpose its authority against a law of the union.