I don’t remember reading the procedure for leaving the union mentioned in the copy of the Constitution I read. Perhaps you could point me to the article that specifically says what you stated, or are you just making it up?
The following excerpt from the U.S. Constitution provides the authorization to add a new state and to “make all needful Rules and Regulations respecting the Territory or other Property belonging to the United States....”, and the secession of a State from the Union is a direct disposition of the Territory of the United States that required the consent of the Congress assembled and the States upon accession or annexation of the same State.
Constitution of the United States
Article. IV.
Section. 3.
New States may be admitted by the Congress into this Union; but no new State shall be formed or erected within the Jurisdiction of any other State; nor any State be formed by the Junction of two or more States, or Parts of States, without the Consent of the Legislatures of the States concerned as well as of the Congress.
The Congress shall have Power to dispose of and make all needful Rules and Regulations respecting the Territory or other Property belonging to the United States; and nothing in this Constitution shall be so construed as to Prejudice any Claims of the United States, or of any particular State.
Doesn’t matter. Civil War gave rise to military industrial complex.
Which now runs US government.