[BroJoeK]

Bull Snipe: "South Carolina should have sued in Federal Court for their secession.
I would expect the Taney Supreme Court would have declared their right to secession as Constitutional."

Sure, Taney maybe.
But the US Constitution clearly assigns such questions to Congress, constitutional amendment or a convention of the states.

What Taney may have done is declare some anti-slavery action of the Federal Government unconstitutional & illegal.
But of course, in 1861 there were no such actions, and without Confederates' withdrawal from Congress there never could have been.

[Bull Snipe]

Exactly where in the Constitution is the article that permits states to secede. That is why it would should have gone to the Supreme Court. The Constitution does not address the issue.