Actually South Carolina seceeded by the vote of a convention appointed by the governor. If that qualifies as legal in your mind then so be it. However, the Supreme Court ruled that acts of secession like South Carolina's were not legal and their opinion's are the ones that matter. It was not an independent country, not in 1861 and not ever. It was not a 'separate and equal nation' just because you say it was. It was a section of the United States in rebellion.
But be that as it may, it only serves to highlight the fact that South Carolina WAS the first state to actually take the illegal action of unilateral secession. Had she tried it thirty years earlier, or had Massachussetts tried it or Connecticut tried it then the actions of the federal government should have been the same.
However, the Supreme Court ruled that acts of secession like South Carolina's were not legal and their opinion's are the ones that matterLOL!! With the main force behind the war as Chief Justice. Face it, Non, that's not only fishy smelling, that's down right crooked