But these laws, it is said, are unconstitutional on account of the motive.  How, Sir, can a law be examined on any such ground?  How is the motive to be ascertained?  One house, or one member, may have one motive; the other house, or another member, another.  One motive may operate to-day, and another to-morrow.  Upon any such mode of reasoning as this, one law might be unconstitutional now, and another law, in exactly the same words, perfectly constitutional next year.  Besides, articles may not only be taxed for the purpose of protecting home products, but other articles may be left free, for the same purpose and with the same motive.  A law, therefore, would become unconstitutional from what it omitted, as well as from what it contained.  Mr. President, it is a settled principle, acknowledged in all legislative halls, recognized before all tribunals, sanctioned by the general sense and understanding of mankind, that there can be no inquiry into the motives of those who pass laws, for the purpose of determining on their validity.  If the law be within the fair meaning of the words in the grant of the power, its authority must be admitted until it is repealed.  This rule, everywhere acknowledged, everywhere admitted, is so universal and so completely without exception, that even an allegation of fraud, in the majority of a legislature, is not allowed as a ground to set aside a law.

But, Sir, is it true that the motive for these laws is such as is stated?  I think not.  The great object of all these laws is, unquestionably, revenue.  If there were no occasion for revenue, the laws would not have been passed; and it is notorious that almost the entire revenue of the country is derived from them.  And as yet we have collected none too much revenue.  The treasury has not been more reduced for many years than it is at the present moment.  All that South Carolina can say is, that, in passing the laws which she now undertakes to nullify, particular imported articles were taxed, from a regard to the protection of certain articles of domestic manufacture, higher than they would have been had no such regard been entertained.  And she insists, that, according to the Constitution, no such discrimination can be allowed; that duties should be laid for revenue, and revenue only; and that it is unlawful to have reference, in any case, to protection.  In other words, she denies the power of DISCRIMINATION.  She does not, and cannot, complain of excessive taxation; on the contrary, she professes to be willing to pay any amount for revenue, merely as revenue; and up to the present moment there is no surplus of revenue.  Her grievance, then, that plain and palpable violation of the Constitution which she insists has taken place, is simply the exercise of the power of DISCRIMINATION.  Now, Sir, is the exercise of this power of discrimination plainly and palpably unconstitutional?