Here you go claiming again that slavery was the only issue. After screaming that you never say that.
But, suppose that secession was only about slavery. Slavery was legal. And, secession is not rebellion, nor is it making war. And, more specifically, secession is not "armed rebellion." The state legislatures met, debated, drew up documents severing their ties with the Union in the same matter state legislatures voted to dissolve the "perpetual" union under the Articles of Confederation, and then to accept the Constitution. All perfectly legal. None of it was prohibited to the States by the US Constitution.
The war was about keeping revenue flowing into the federal treasury first and foremost. That was the reason "honest" Abe gave for it.
And, again, if, as you have again said
It was a rebellion to perpetuate slavery.
and the only thing the seven southern states was interested in was slavery, why didn't they stay in the Union and ratify the Corwin Amendment?
In fact, that four states did not issue legislation dissolving their bonds with the Union until after Lincoln tried to coerce them into invading the states that had left the Union, and threatened to march Federal troops through them, in what they saw as an unconstitutional abuse of federal power, you "it was about slavery" falls flaming to the floor as the falsehood that it is.
Was slavery in the mix of reasons? Yes, it was. Was it, as you imply, the only reason? No. Secession was not only about slavery. And the War was decidedly not about slavery. In fact, in his first inaugural address, "Honest" Abe basically said that he was willing to let them go, if the tripled Morrill Tariffs from federal customs houses still flowed into Washington.
Here are some that I'm sure you will dismiss:
From the Baltimore Exchange, 23d ult. (i.e. April 23, 1861)
Interview between Messengers of Peace and Mr. Lincoln
The Baltimore Sun has the following in relation to the interview between the President and a committee of the "Young Men’s Christian Association of Baltimore," it says:
We learn that a delegation from five of the Young Men's Christian Associations of Baltimore, consisting of six members of each, yesterday proceeded to Washington for an interview with the President, the purpose being to intercede with him in behalf a peaceful policy, and to entreat him not to pass troops through Baltimore or Maryland. The Rev. Dr. Fuller, of the Baptist church, accompanied the party, by invitation, as chairman, and the conversation was conducted mainly between him and Mr. Lincoln, and was not heard entire by all the members of the Convention.
Our informant, however, vouches for what we now write. He states that upon the introduction, they were received very cordially by Mr. Lincoln—a sort of rude familiarity of manner – and the conversation opened by Dr. Fuller seeking to impress upon Mr. Lincoln the vast responsibility of the position he occupied, and that upon him depended the issues, of peace or war—on one hand a terrible, fratricidal conflict, and on the other peace. “But” said Mr. Lincoln, what am I to do?”
“Why, sir, let the country know that you are disposed to recognize the independence of the Southern States. I say nothing of secession; recognize the fact that they have formed a Government of their own; that they will never be united again with the North, and peace will instantly take the place of anxiety and suspense, and war may he averted.” “AND WHAT SHALL BECOME OF THE REVENUE? I SHALL HAVE NO GOVERNMENT—NO RESOURCES?” (Emphasis added, not in the original)
Dr. Fuller expressed the opinion that the Northern States would constitute an imposing government and furnish revenue, but our informant could not follow the exact terms of the remark.
(Reprinted in the Memphis Daily Avalanche May 8th 1861, pg.1, col. 4.)
Second episode:
At an interview between Virginia Convention Delegate John B. Baldwin and President Lincoln on April 4th, 1861, Baldwin suggested to Lincoln that “in order to prevent the possibility of any collision or clash of arms interfering with this effort at a pacific settlement, I would declare the purpose (not in any admission of want of right at all, but with a distinct protest of the right, to place the forces of the United States wherever in her territory you choose) to withdraw the forces from Sumter and Pickens, declaring that it was done for the sake of peace, in the effort to settle this thing; … He said something about the withdrawal of the troops from Sumter on the ground of military necessity. Said I, "that will never do under heaven. You have been President a month to-day, and if you intended to hold that position you ought to have strengthened it, so as to make it impregnable. To hold it in the present condition of force there is an invitation to assault. Go upon higher ground than that. The better ground than that is to make a concession of an asserted right in the interest of peace."-"Well," said he, "WHAT ABOUT THE REVENUE? WHAT WOULD I DO ABOUT THE COLLECTION OF DUTIES?" (Emphasis added, not in the original)
Said I, "Sir, how much do you expect to collect in a year?" Said he, "Fifty or sixty millions." "Why sir," said I, "four times sixty is two hundred and forty. Say $250,000,000 would be the revenue of your term of the presidency; what is that but a drop in the bucket compared with the cost of such a war as we are threatened with? Let it all go, if necessary; but I do not believe that it will be necessary, because I believe that you can settle it on the basis I suggest." He said something or other about feeding the troops at Sumter. I told him that would not do. Said I, "You know perfectly well that the people of Charleston have been feeding them already. That is not what they are at. They are asserting a right. They will feed the troops and fight them while they are feeding them. They are after the assertion of a right. Now, the only way that you can manage them is to withdraw from them the means of making a blow until time for reflection, time for influence which can be brought to bear, can be gained, and settle the matter. If you do not take this course, if there is a gun fired at Sumter-I do not care on which side it is fired-the thing is gone." "Oh," said he, "sir, that is impossible." Said I, "Sir, if there is a gun fired at Sumter, as sure as there is a God in heaven the thing is gone. Virginia herself, strong as the Union majority is now, will be out in forty-eight hours."
(From testimony before the Reconstruction Committee of the US Congress by Mr. Baldwin in 1866
And, I'm going to ask once again: Where in the Constitution is there any clause that prohibits any state from withdrawing from the Union? Please cite the text.