The Founders rejected any thoughts of invading, coercing and subjugating a State within the proposed union; any such action by the other States or the agent created by the States would be war and grounds for dissolution of the agreement.
In fact, to prevent the federal agent and its officers from engaging in an attack upon a State, Article III, Section 3 states that “Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving the Aid and Comfort.”
www.Circa1865.org The Great American Political Divide
“One of the better summaries of the prevalent Constitutional theory at that time (December 1861-May 1861] has been made by black scholar, professor and prolific author Dr. Walter Williams. Here is what he writes in one of his columns:
“During the 1787 Constitutional Convention, a proposal was made that would allow the federal government to suppress a seceding State. James Madison rejected it, saying, “A union of the States containing such an ingredient seemed to provide for its own destruction. The use of force against a State would look more like a declaration of war than an infliction of punishment and would probably be considered by the party attacked as a dissolution of all previous compacts by which it might be bound.”
In fact, the ratification documents of Virginia, New York and Rhode Island, explicitly said they held the right to resume powers delegated should the federal government become abusive of those powers. The Constitution never would have been ratified if States thought they could not regain their sovereignty – in a word, secede.
On March 2, 1861, after seven States seceded and two days before Abraham Lincoln’s inauguration, Senator James R. Doolittle of Wisconsin proposed a constitutional amendment that read: “No State or any part thereof, heretofore admitted or hereafter admitted to the union, shall have the power to withdraw from the jurisdiction of the United States.”
Several months earlier, Reps. Daniel E. Sickles of New York, Thomas B. Florence of Pennsylvania, and Otis S. Ferry of Connecticut proposed a constitutional amendment to prohibit secession.
Here is a question for the reader: Would there have been any point of offering these amendments if secession were already unconstitutional?”
(The Land We Love: The South and Its Heritage, Boyd D. Cathey, Scuppernong Press, 2018, excerpt pg. 7)