The preamble rests its justification on these grounds: It assumes as a fact, that the obnoxious laws, although they purport to be laws for raising revenue, were in reality intended for the protection of manufactures, which purpose it asserts to be unconstitutional; that the operation of these laws is unequal; that the amount raised by them is greater than is required by the wants of the government; and, finally, that the proceeds are to be applied to objects unauthorized by the Constitution. These are the only causes alleged to justify an open opposition to the laws of the country, and a threat of seceding from the Union, if any attempt should be made to enforce them. The first actually acknowledges that the law in question was passed under power expressly given by the Constitution, to lay and collect imposts; but its constitutionality is drawn in question from the motives of those who passed it. However apparent this purpose may be in the present case, nothing can be more dangerous than to admit the position that an unconstitutional purpose, entertained by the members who assent to a law enacted under a constitutional power, shall make that law void; for how is that purpose to be ascertained? Who is to make the scrutiny? How often may bad purposes be falsely imputed? In how many cases are they concealed by false professions? In how many is no declaration of motive made? Admit this doctrine, and you give to the States an uncontrolled right to decide, and every law may be annulled under this pretext. If, therefore, the absurd and dangerous doctrine should be admitted, that a State may annul an unconstitutional law, or one that it deems such, it will not apply to the present case.