“It’s funny, but all you ‘right to secede’ folks always overlook one thing: If the south was so sure secession was legal, why didn’t they just seek a ruling from the Supreme Court to put the stamp of law to it?”
They didn’t have to. They had already seceded, and thus were not under the jurisdiction of SCOTUS, and therefore any SCOTUS ruling would be inapplicable to the Confederate States of America. Besides, they believed that while they were still part of the Union, the 10th Amendment allowed for secession; and afterwards (i.e., after secession), it didn’t matter.
That’s right - instead of seeking the rule of law they cut & ran. Look how that worked out...