First Inaugural Address March 4, 1861
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 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.
Message to Congress in Special Session July 4, 1861
The principle [secession] itself is one of disintegration, and upon which no government can possibly endure.