In the quotations which we have made from the pamphlet of Mr. McDuffie, we have employed to a very moderate extent the _argumentum ad hominem_, which, as our readers are aware, might be carried without difficulty a great deal farther. There have probably been very few cases, in the history of this or any other country,--especially relating to matters of so much importance,--in which individuals have placed themselves before the public, in a position so diametrically opposite to that which they occupied but a short time before. Their inconsistency is equally glaring in reference to the nature of the evil of which they complain, and the means by which they propose to remedy it. But a few years ago, these very persons not only supported and professed to believe in the policy of protecting domestic industry, but actually originated the plan, and employed the whole weight of their talents and influence in carrying it through Congress. At the same time, they denounced the claim of a right in the States to annul the acts of the General Government, as anarchy itself. Now, the protecting policy is not only not advantageous but utterly ruinous to the country; and not only ruinous but unconstitutional, and not only unconstitutional but so plainly and palpably unconstitutional, as to justify a resort to the most desperate extremities to get rid of it. Now, the right of the States to annul at discretion the acts of the General Government is not only not anarchy itself, but is the simplest and most beautiful part of the whole machinery of our political institutions. It would be easy to collect from the writings and speeches of these gentlemen at the two periods alluded to, whole pages of passages, presenting, on the same authority, exactly the _pro_ and _con_ of every prominent point in the argument. This has in fact been done to a considerable extent by Mr. Carey, and if the subject were not a serious one, the contrast would be irresistibly amusing. Our limits will not permit us to enlarge upon this point, and the strength of the direct argument renders it unnecessary. In general, we are not disposed to insist too rigorously upon formal party consistency, and are willing to allow to political men a reasonable latitude in reconsidering their opinions, and adapting their abstract principles to the circumstances under which they are called to act. But in a case so very peculiar as this, where the party is so clearly bound to put himself in the right in the great court of public opinion, he certainly gives his opponents a fearful advantage when he enables them, on every leading point, to _condemn_ him unequivocally and peremptorily _out of his own mouth_.