Why?
Because it is not sanctioned by US law. The theory is not rightly deduced or inferred. It's erroneous. Anti-republican. Anti-American.
Why?
"Plainly, the central idea of secession, is the essence of anarchy. A majority, held in restraint by constitutional checks and limitations, and always changing easily with deliberate changes of popular opinions and sentiments, is the only true sovereign of a free people. Whoever rejects it, does, of necessity, fly to anarchy or to despotism. Unanimity is impossible; the rule of a minority, as a permanent arrangement, is wholly inadmissible; so that, rejecting the majority principle, anarchy or despotism in some form is all that is left."
A. Lincoln, 7/4/61
Walt