Read the ordinances of secession passed by the various southern states. A couple of them may not mention slavery as a primary cause of secession, but most do, loud and clear.
I’m sorry. I should have said from Lincolns’ point of view.
In referring to the secession documents, you said:
“A couple of them may not mention slavery as a primary cause of secession, but most do.”
Actually that is not factual.
None of the original 7 and eventual 11 ordinances mentioned slavery as a cause of their decision to leave the Union.
However, four states published their reasoning in individual state decrees, which of course, were not legally representative of the state actions.
Therefore, any notion that these documents were formal, legal explanations is totally false.