"Honest" Abe, huh? You forgot to mention that a few years earlier Massachusetts threatened to seceed, and there was no great debate (that I am aware of) regarding the "legality". Double-standards have always been the halmarks of liberalism.
Well, you need to be more aware.
Here is what Andrew Jackson said when S. Carolina first rumbled with treason.
"So obvious are the reasons which forbid this secession, that it is necessary only to allude to them. The union was formed for the benefit of all. It was produced by mutual sacrifices of interests and opinions. can those sacrifices be recalled? Can the states, who magnanimously surrendered their title to the territories of the west, recall the grant? Will the inhabitants of the inland states agree to pay the duties that may be imposed without their assent by those on the Atlantic or the Gulf, for their own benefit? Shall there be a free port in one state, and onerous duties in another. No one believes that any right exists in a single state to involve the other in these and countless other evils, contrary to the engagements solemnly made.
Every one must see that the other states, in self-defence, must oppose it at all hazards.
These are the alternatives that are presented by the convention--a repeal of all the acts for raising revenue, leaving the government without the means of support; or an acquiescence in the dissolution of our Union by the secession of one of its members, When the first was proposed, it was known that it could not be listened, to for a moment. It was [Page 592] known, if force was applied to oppose the execution of the laws, that it must be repelled by force; that Congress could not, without involving itself in disgrace, and the country in ruin, accede to the proposition; and yet, if this is not done on a given day, or if any attempt is made to execute the laws, the state is, by the ordinance, declared to be out of the Union. The majority of a convention assembled for the purpose have dictated these terms, or rather this rejection of all terms, in the name of the people of South Carolina. It is true that the government of the state speaks of the submission of their grievances to a convention of all the states, which, he says, they "sincerely and anxiously seek and desire." Yet this obvious and constitutional mode of obtaining the sense of the other states on the construction of the federal compact, and amending it, if necessary, has never been attempted by those who have urged the state on to this destructive measure. The state might have proposed the call for a general convention to the other states, and Congress, if a sufficient number of them concurred, must have called it.
But the first magistrate of South Carolina, when he expressed a hope that, "on a review, by Congress and the functionaries of the general government, of the merits of the controversy," such a convention will be accorded to them, must have known that neither Congress, nor any functionary of the general government, has authority to call such a convention, unless it may be demanded by two thirds of the states. This suggestion, then, is another instance of the reckless inattention to the provisions of the Constitution with which this crisis has been madly hurried on; or of the attempt to persuade the people that a constitutional remedy had been sought and refused. If the legislature of South Carolina "anxiously desire" a general convention to consider their complaints, why have they not made application for it in the way the Constitution points out? The assertion that they "earnestly seek it" is completely negatived by the omission.
Elliot, Jonathan, 1784-1846.; United States. Constitutional Convention (1787) , The Debates in the several state conventions on the adoption of the federal Constitution, as recommended by the General Convention at Philadelphia in 1787. "Elliot's Debates." Philadelphia : J. B. Lippincott & co., 1836-59. 5 v., vol IV, pp 582-592
Secession is treason.
Walt