, 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 is it 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."

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 pe