Cut NonSensical some slack. He's still fighting the Supreme Court decision that states have the right to secede from the Union. Truth is, the Court never ruled on that case -- a no decision is a yes in my book. (Some day this issue will be reintroduced to the SCOTUS.) But, NS can't help it if she/he/it's ("shits" for short) obsessed.
I did like your theory, not that it could have happened, but it would have been the biggest display of hypocracy of ever witnessed. Of course, the other way in which the war could have been avoided would have been if the US had have removed its troops from sovereign states, especially South Carolina.
Sure they did. Texas v. White. 1869. The court found that secession was not Constitutional. Look it up.