re: If secession was legal then what right did the North have to keep the South in the USA?

quote:

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The 10th Amendment says no!

No mechanisms defined means that right is ceded to the state(s).

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I mean that argument seems reasonable on its, but now there is SCOTUS precedent against it as well, and others reference other parts of the text against it (Article 1 Section 10; a perfect union).

But my issue is that if the forming of a union requires consent of the state and the federal government, then the divorce from this "perfect union" should require mutual consent from the parties of that unuon.