you almost have it, except when you say the rest of the states would have to agree to any state secession. Can you cite language from the constitution to support that claim?
Nope, but I can cite language that says Congress can deal with parties that place themselves in a status of insurrection against a lawful government.
If a State attempts to unilaterally secede, they have placed themselves in revolt against the United States. (Merriam-Webster
Insurrection: an act or instance of revolting against civil authority or an established government.)
Now on the other hand, if Texas asks for permission to leave the Union, and upon negotiation there is a equitable process defined that is acceptable to Texas and the other 49 States, then Texas can leave the Union. I mean really, once the other States agree to let Texas leave the Union - on the conditions negotiated to deal with debt, property, citizenship, currency, etc.) - then there would be no actions against Texas.
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