That was not the contemporary opinion.
"South Carolina...cannot get out of this Union until she conquers this government. The revenues must and will be collected at her ports, and any resistance on her part will lead to war. At the close of that war we can tell with certainty whether she is in or out of the Union. While this government endures there can be no disunion...If the overt act on the part of South Carolina takes place on or after the 4th of March, 1861, then the duty of executing the laws will devolve upon Mr. Lincoln. The laws of the United States must be executed-- the President has no discretionary power on the subject -- his duty is emphatically pronounced in the Constitution. Mr. Lincoln will perform that duty. Disunion by armed force is treason, and treason must and will be put down at all hazards. The Union is not, and cannot be dissolved until this government is overthrown by the traitors who have raised the disunion flag. Can they overthrow it? We think not."
Illinois State Journal, November 14, 1860
The Illinois State Journal was pretty much speaking for the president-elect.
The Militia Act of 1792 as amended in 1795 gives the president the clear power to put down insurrection against the United States. The Supreme Court approved the propriety of the president's actions in the Prize Case ruling. Just because you never heard of it doesn't amount to a hill of beans.
Walt