The Supreme Court is the final arbiter on what is constitutional or unconstitutional in our system of government. In Cohens vs Virginia (1821) they made the determination that the Constitution was formed by all the people of the United States and could only be changed by all the people.
“The people made the constitution, and the people can unmake it. It is the creature of their will, and lives only by their will. But this supreme and irresistible power to make or to unmake, resides only in the whole body of the people; not in any sub-division of them. The attempt of any of the parts to exercise it is usurpation, and ought to be repelled by those to whom the people have delegated their power of repelling it.” [19 U.S. 264] 1821
Don’t like it, get an amendment passed to allow a state to leave, or the supreme court to reveres this ruling. That’s how our system works.
Actually, the Constitution itself mentions exceptions.
Don’t like it, get an amendment passed... That’s how our system works.
And how, precisely, would such an amendment be passed? By "the whole body of the people" voting in a national election?
Of course not - the Constitution specifies, in writing, that amendments are adopted "when ratified by the Legislatures of three fourths of the several States, or by Conventions in three fourths thereof".
THAT'S how our system works...