JJ, Am thinking you're right on SCOTUS. And, you're not really being too vague at all. There was originally some details agreeing to possible succession when Texas became a state and was split up to become one though. Think Texas is huge now? It was larger yet before it became a state, much, much more so. Much of The Republic of Texas was divided up to become other states. Republic of Texas originally stretched up to Canadian border if remember right? Possibly came close to rivaling Alaska in size? There's one heck of a lot of varying and interesting historical and legal detail on Texas.BobM, I'm not absolutely certain but I believe even with Texas, secession would be unconstitutional as SCOTUS has ruled (can't quote the case off hand). However there is some quirk somewhere, in the Texas state charter I think, that still allows for the state to break itself up into 4 smaller, individual and defined states.
Don't mean to be so vague, just can't recall the actual details.