Whoever argues against these principles argues against the practicability of all free governments. And whoever admits these, must admit, or cannot deny, that power is as safe in the hands of Congress as in those of other representative bodies. Congress is not irresponsible. Its members are agents of the people, elected by them, answerable to them, and liable to be displaced or superseded, at their pleasure; and they possess as fair a claim to the confidence of the people, while they continue to deserve it, as any other public political agents. If, then, Sir, the manifest intention of the Convention, and the contemporary admission of both friends and foes, prove anything; if the plain text of the instrument itself, as well as the necessary implication from other provisions, prove anything; if the early legislation of Congress, the course of judicial decisions, acquiesced in by all the States for forty years, prove any thing,--then it is proved that there is a supreme law, and a final interpreter. My fourth and last proposition, Mr. President, was, that any attempt by a State to abrogate or nullify acts of Congress is a usurpation on the powers of the general government and on the equal rights of other States, a violation of the Constitution, and a proceeding essentially revolutionary. This is undoubtedly true, if the preceding propositions be regarded as proved. If the government of the United States be trusted with the duty, in any department, of declaring the extent of its own powers, then a State ordinance, or act of legislation, authorizing resistance to an act of Congress, on the alleged ground of its unconstitutionality, is manifestly a usurpation upon its powers. If the States have equal rights in matters concerning the whole, then for one State to set up her judgment against the judgment of the rest, and to insist on executing that judgment by force, is also a manifest usurpation on the rights of other States. If the Constitution of the United States be a government proper, with authority to pass laws, and to give them a uniform interpretation and execution, then the interposition of a State, to enforce her own construction, and to resist, as to herself, that law which binds the other States, is a violation of the Constitution. If that be revolutionary which arrests the legislative, executive, and judicial power of government, dispenses with existing oaths and obligations of obedience, and elevates another power to supreme dominion, then nullification is revolutionary. Or if that be revolutionary the natural tendency and practical effect of which are to break the Union into fragments, to sever all connection among the people of the respective States, and to prostrate this general government in the dust, then nullification is revolutionary.