It is known to Senators who have served with me here, that I have, for many years, advocated, as an essential attribute of State sovereignty, the right of a State to secede from the Union. Therefore, if I had not believed there was justifiable cause; if I had thought that Mississippi was acting without sufficient provocation, or without an existing necessity, I should still, under my theory of the Government, because of my allegiance to the State of which I am a citizen, have been bound by her action. I, however, may be permitted to say that I do think she has justifiable cause, and I approve of her act. I conferred with her people before that act was taken, counseled them then that if the state of things which they apprehended should exist when the convention met, they should take the action which they have now adopted. I hope none who hear me will confound this expression of mine with the advocacy of the right of a State to remain in the Union, and to disregard its constitutional obligations by the nullification of the law. Such is not my theory. Nullification and secession, so often confounded, are, indeed, antagonistic principles. Nullification is a remedy which it is sought to apply within the Union, and against the agent of the States. It is only to be justified when the agent has violated his constitutional obligations, and a State, assuming to judge for itself, denies the right of the agent thus to act, and appeals to the other States of the Union for a decision; but when the States themselves, and when the people of the States, have so acted as to convince us that they will not regard our constitutional rights, then, and then for the first time, arises the doctrine of secession in its practical application. A great man, who now reposes with his fathers, and who has often been arraigned for a want of fealty to the Union, advocated the doctrine of nullification because it preserved the Union. It was because of his deep-seated attachment to the Union--his determination to find some remedy for existing ills short of a severance of the ties which bound South Carolina to the other States, that Mr. Calhoun advocated the doctrine of nullification, which he proclaimed to be peaceful--to be within the limits of State power, not to disturb the Union, but only to be a means of bringing the agent before the tribunal of the States for their judgment.