Once this power was threatened to be assumed by Massachusetts, now by South Carolina, and how and by what State it will next be exercised, or what vital power it may next strike from the Constitution, it is impossible to predict; but, if permitted in one State, it will be exercised by all, till not a vestige remains of the Constitution of the Union. Suppose the Tariff repealed by Congress, nullification may annul the repealing law. Louisiana may, in the exercise of her right of ultimate judgment, declare that the repealing law is unconstitutional, upon the pretext that it destroys rights vested by the first law and violates the plighted faith of the Government, insist on the collection of duties under the first law, pass her ordinance, array her State officers against those of the Union, and thus destroy the commerce of Mississippi, and of all the Western States, or compel the collection of the present duties. Or she may say that, if Congress possesses no power to lay duties which will operate an incidental protection, Louisiana possesses the reserved right of imposing duties for that purpose; that each State possessed it before it became a member of the Union; that duties for revenue only can be collected by the General Government, and that the residuary power to lay duties for protection is one of the powers of a sovereign State; that she will exercise it, and impose protecting duties on imports, and thus we shall have various and conflicting State tariffs from Maine to Louisiana (the very object which the Constitution was designed to prevent); but if Louisiana alone adopt the measure, the commerce of the West is prostrate at her feet.