You’re still trying miserably to resurrect your absurd assertion. Of course secession isn’t precluded by a union that was freely joined, but THAT is not what happened. Lincoln went against all the wishes of the founders, IMO.
But, try as you may, this still doesn’t resolve your refusal to accept a non-historical definition of civil war.
A right granted by God may not be forsworn by scribblings on paper by men.
There is no means by which you can legally bind a people and compel them to give up a right granted by God.
The founders of this nation clearly recognized that Independence is a right granted by God, and as such it may not be subjugated to "contracts", or "agreements" to abrogate it.
It is absolute, and unalienable.