[Svartalfiar]

In order for a state to legally leave the Union it would at the least require law sanction.

Why? The Constitution doesn't mention anything about secession. The only parts that could apply would be, primarily, the Tenth Amendment, or, tangentially, creating new states out of existing ones. That is the closest occurrence actually delineated in the document, and would therefore lead to an idea of the approval of both the state Legislature and the Congress. But, without explicit methods delineated, all we have to go on is the Tenth, meaning any power of Secession is wholey retained by the people (states).

Most of the Southern states were created by the federal government and it had property in all of them.

Correct. And the farther west you go, the more state property the FedGov has owned. Way beyond a few docks or armories or needful buildings. However, once a territory or other becomes a state, it gains its own sovereignty, same as the 13 original colonies, same as Texas when we joined the Union. The only real argument to be made here is how legitimate Federal property is to be treated. Kept by US? Granted to the seceding state? Purchased by the state? Etc?

[arrogantsob]

There was two sovereignties involved here. There was no conditional ratification, no right to revoke and no right to seize federal property. This was settled in a letter from Madison to Hamilton during the NY state ratification convention. NY was holding out for the right to leave and Madison held that it was unacceptable. What would be sufficient grounds to leave, just about anything?

The Articles of Confederation were superseded by the “more perfect union” of the federation.

Texas had no special rights when it joined the union, that, like most of these issues have long been settled and hardly worth the time to discuss them when so much more important things are in play.