Section 3. New states may be admitted by the Congress into this union; but no new states 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.
Section 4. The United States shall guarantee to every state in this union a republican form of government, and shall protect each of them against invasion; and on application of the legislature, or of the executive (when the legislature cannot be convened) against domestic violence.
Now you're saying Congress can't admit a state? That was the basis for your horribly flawed argument in the first place!?
How you could ever stumble into that conclusion based on anything I've posted is beyond me. You must be hearing voices. Again.
What I'm saying is that Congress does more than admit states, it creates them. Alabama did not exist before the other states allowed it to through a vote in Congress. Ohio was just a figment of the people's imagination until Congress admitted it as a state. Since states are created by Congress and since any post-admission change to their status - splitting, combining, changing their border by a fraction of an inch - has to be approved by Congress, then how you all can come to the conclusion that the approval of the other states is not needed before leaving is something that never ceases to amaze me.