I also forgot to mention that the principle of secession was being taught in the constitution classes at West Point in the early 1800s, classes and textbooks that the US government was paying for. In William Rawle's Views of the Constitution it said that
"It depends of the state itself to retain or abolish the principle of representation, because it depends on itself whether it will continue a member of the Union. To deny this right would be inconsistent with the principle of which all our political systems are founded, which is, that the people have in all cases, a right to determine how they will be governed.
This right must be considered as an ingredient in the original composition of the general government, which though not expressed, was mutually understood."
Rawle also had this to say about secession:
The secession of a state from the Union depends on the will of the people of such state. The people alone as we have already seen, hold the power to alter their constitution. But in any manner by which a secession is to take place, nothing is more certain that the act should be deliberate, clear, and unequivocal. To withdraw from the Union is a solemn, serious act. Whenever it may appear expedient to the people of a state, it must be manifest in a direct and unequivocal manner."
(As a note: Rawle was a Northerner [born in Philadelphia], a contemporary of the Founders, and his book was warmly received when published. The North American Review, a journal of Boston political orthodoxy, blessed his book as an "intelligent guide.")
As an American, Rawle knew that the Union was dear to all and offered many advantages to member states. But as an American, he also knew that when the people of a state felt that those advantages no longer existed and that the Union had become a thread to their happiness, the very reason for the Union's existence was no longer valid.
Alexis de Tocqueville, in Democracy in America, said:
"The Union was formed by the voluntary agreement of the States; and in uniting together they have not forfeited their nationality, nor have they been reduced to the condition of one and the same people. If one of the States choose to withdraw from the compact, it would be difficult to disprove its right of doing so, and the Federal Government would have no means of maintaining its claims directly either by force or right."
Well I think it's safe to say that the Southern people were certainly inclined to rebel. But they did lack the power, didn't they?
The secession of a state from the Union depends on the will of the people of such state. The people alone as we have already seen, hold the power to alter their constitution...But in any manner by which a secession is to take place, nothing is more certain that the act should be deliberate, clear, and unequivocal. To withdraw from the Union is a solemn, serious act. Whenever it may appear expedient to the people of a state, it must be manifest in a direct and unequivocal manner."
There is a reason why I inserted the ellipses in your quote; it's because you left out a whole section of the paragraph. That part reads, "The state legislatures have only to perform certain organical operations in respect to it. To withdraw from the Union comes not within the general scope of their delegated authority. There must be an express provision to that effect inserted in the state constitutions. This is not at present the case with any of them, and it would perhaps be impolitic to confide it to them. A matter so momentous, ought not to be entrusted to those who would have it in their power to exercise it lightly and precipitately upon sudden dissatisfaction, or causeless jealousy, perhaps against the interests and the wishes of a majority of their constituents." So if, in Rawle's opinion, the state legislatures lacked the constitutional authority to secede without an addition to their constitution then when were those provisions added and what is the wording?