This, Sir, was the first great step. By this the supremacy of the Constitution and laws of the United States is declared. The people so will it. No State law is to be valid which comes in conflict with the Constitution, or any law of the United States passed in pursuance of it. But who shall decide this question of interference? To whom lies the last appeal? This, Sir, the Constitution itself decides also, by declaring, "_that the judicial power shall extend to all cases arising under the Constitution and laws of the United States_." These two provisions cover the whole ground. They are, in truth, the keystone of the arch! With these it is a government; without them it is a confederation. In pursuance of these clear and express provisions, Congress established, at its very first session, in the judicial act, a mode for carrying them into full effect, and for bringing all questions of constitutional power to the final decision of the Supreme Court. It then, Sir, became a government. It then had the means of self-protection; and but for this, it would, in all probability, have been now among things which are past. Having constituted the government, and declared its powers, the people have further said, that, since somebody must decide on the extent of these powers, the government shall itself decide; subject, always, like other popular governments, to its responsibility to the people. And now, Sir, I repeat, how it is that a State legislature acquires any power to interfere? Who, or what, gives them the right to say to the people, "We, who are your agents and servants for one purpose, will undertake to decide that your other agents and servants, appointed by you for another purpose, have transcended the authority you gave them!" The reply would be, I think, not impertinent, "Who made you a judge over another's servants? To their own masters they stand or fall." [Sidenote: Revolution a law to itself.] [Sidenote: The people have reposed power in the general government.] Sir, I deny this power of State legislatures altogether. It cannot stand the test of examination. Gentlemen may say that in an extreme case a State government might protect the people from intolerable oppression. Sir, in such a case the people might protect themselves without the aid of the State governments. Such a case warrants revolution. It must make, when it comes, a law for itself. A nullifying act of a State legislature cannot alter the case, nor make resistance any more lawful. In maintaining these sentiments, Sir, I am but asserting the rights of the people. I state what they have declared, and insist on their right to declare it. They have chosen to repose this power in the general government, and I think it my duty to support it, like other constitutional powers.