I think it has nothing to do with Secession
i.e.
Amendment X
The powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the states respectively, or to the people.
and nowhere in the Constitution does it give the Federal Government the right to prevent a state from leaving the Union.
If it did, we would not be having this discussion. It has never been clearly laid out because it has never existed.
Ever
To presume that since the right to unilateral secession exists because it is not explicitly forbidden, then you must also assume that the Federal government had a unilateral right to expel any state, even against its wishes, since that is also not explicitly forbidden.
In other words by your reading of the Constitution, the Federal Government could have "traded" Georgia to Spain or Great Britain for say Mexico or Canada, and the people of Georgia would have no say in the matter.
Insurrection covers the issue. The Tenth does not justify nor legalize insurrection. As has been shown above the Union was designed to be and was called "perpetual" repeatedly and changing the form of the government of that Union did not change the perpetualness of that Union. Nor could insurrections.
Show me ONE word spoken about secession during the Convention. It was inconceivable to the Founders and you cannot show me ONE word which they spoke considering secession to be acceptable or constitutional. And given the growth of the Constitution out of the Articles there was no necessity to address the already addressed nature of the Union. For the Founders it was settled.
A constitution allowing secession would have been worthless and not even Jefferson supported such an idea. Not that he was in any way a Constitutional expert.
Plus you have the little problem that the states were the creation of the Continental Congress. None existed until it asked them to write state constitutions and form as states. Our common belief that we were all Americans pre-dated both the states and the Union. Creation of the Union and the Constitution was an act of the American People not states.