“The way most of them entered was with the consent of the other states as expressed through a vote in both houses of Congress. Are you suggesting that they tried to leave the same way?”
If that were the way they enter the Union yes, but thats not the way they enter the union. Congress passes an enabling act which is like an invitation, and the State accepts, generally thou convention or referendum.
In the case of the original 13 the invitation was in the original convention.
So yes they did leave the same way they entered, as you do not need an invitation to leave someones house, you only need one to enter.
Nonsense. Read the Constitution, Article IV. The actions and/or desires of the territories are not part of the process. Indeed, territories can petition for years for statehood and Congress can ignore them, witness Kansas and Colorado. Constitutionally the sole party to creating a state is Congress. And once allowed to join, states cannot combine, split, or change their borders by a fraction of an inch without Congressional approval. States exist because of Congress. They can be altered only with the approval of Congress. Clearly congressional approval is needed to leave as well.
So yes they did leave the same way they entered, as you do not need an invitation to leave someones house, you only need one to enter.
Changing your story I see.