The only way for a state to secede lawfully is through the amendment process in Article V.
It shouldn't be forgotten that the Arts. of Confed were a big flop and people -knew- they were a big flog at the time They in many cases reluctantly agreed to the United States taking a national form under the Constitution. But they knew that was what was being done.
The framers -clearly- wanted to establish nationality and Washington, Madison and Jefferson are only the most prominent.
A state may NOT leave the union unilaterally. To suggest it may perverts what the framers intended.
A whole blizzard of obscure quotations cannot change what the framers wanted.
People shouldn't let dissatisfaction with the government today cloud ther view of what the framers intended.
How did the original colonies enter? And where is the prohibition against leaving? Just curious.