Illegal and forbidden are not synonyms. Political actions especially with respect to territorial integrity can both be illegal and allowed to happen i.e. not forbidden.

>Well, as both Americans and Spanish might say, "we had a war to settle that issue."

My main point was reacting to your statement above. A particular set of wars does not settle those issues.

What prevents a secessionist legal action to be heard by the Supreme court and for them to overturn the Texas v. White decision?