Ignoring for a moment the nonsense in the first part of your statement, they violated the Constitution in their acts of unilateral secession.
Now back up and prove it's nonsense.
..... they violated the Constitution in their acts of unilateral secession.
No, they didn't. Make a treaty, unmake a treaty -- a sovereign isn't someone a judge can overrule.
But you are recalcitrant and slothful, so let's try it this way:
Who is the sovereign of the United States of America? What is his name, where does he live?
To put it a little more bluntly: Who's your daddy, servile belly-crawler? Who do you crawl for?