It will not be denied, Sir, that this authority naturally belongs to all governments.  They all exercise it from necessity, and as a consequence of the exercise of other powers.  The State governments themselves possess it, except in that class of questions which may arise between them and the general government, and in regard to which they have surrendered it, as well by the nature of the case as by clear constitutional provisions.  In other and ordinary cases, whether a particular law be in conformity to the constitution of the State is a question which the State legislature or the State judiciary must determine.  We all know that these questions arise daily in the State governments, and are decided by those governments; and I know no government which does not exercise a similar power.

Upon general principles, then, the government of the United States possesses this authority; and this would hardly be denied were it not that there are other governments.  But since there are State governments, and since these, like other governments, ordinarily construe their own powers, if the government of the United States construes its own powers also, which construction is to prevail in the case of opposite constructions?  And again, as in the case now actually before us, the State governments may undertake, not only to construe their own powers, but to decide directly on the extent of the powers of Congress.  Congress has passed a law as being within its just powers; South Carolina denies that this law is within its just powers, and insists that she has the right so to decide this point, and that her decision is final.  How are these questions to be settled?

In my opinion, Sir, even if the Constitution of the United States had made no express provision for such cases, it would yet be difficult to maintain, that, in a Constitution existing over four-and-twenty States, with equal authority over all, one could claim a right of construing it for the whole.  This would seem a manifest impropriety; indeed, an absurdity.  If the Constitution is a government existing over all the States, though with limited powers, it necessarily follows, that, to the extent of those powers, it must be supreme.  If it be not superior to the authority of a particular State, it is not a national government.  But as it is a government, as it has a legislative power of its own, and a judicial power coextensive with the legislative, the inference is irresistible that this government, thus created by the whole and for the whole, must have an authority superior to that of the particular government of any one part.  Congress is the legislature of all the people of the United States; the judiciary of the general government is the judiciary of all the people of the United States.  To hold, therefore, that this legislature and this judiciary are subordinate in authority to the legislature and judiciary of a single State, is doing violence to all common sense, and overturning all established principles.  Congress must judge of the extent of its own powers so often as it is called on to exercise them, or it cannot act at all; and it must also act independent of State control, or it cannot act at all.