The Legality of Seccession in Antebellum America

[Xiahou]

There is no provision in the Constitution for a state to leave the union. No state would have any chance of leaving without the consent of the federal government and the rest of the states.... or by rebellion.

Texas v. White:

When, therefore, Texas became one of the United States, she entered into an indissoluble relation. All the obligations of perpetual union, and all the guaranties of republican government in the Union, attached at once to the State. The act which consummated her admission into the Union was something more than a compact; it was the incorporation of a new member into the political body. And it was final. The union between Texas and the other States was as complete, as perpetual, and as indissoluble as the union between the original States. There was no place for reconsideration or revocation, except through revolution or through consent of the States.