But they are outside the scope in very important ways this glosses over and which does make them much more sovereign than a state, such as sin taxes (cigarettes) and gun law enforcement (a PMC was incorporated in and trading fully automatic weapons through Indian territory). The basis for those is what is important.
I'm not totally sold on this interpretation, I've interacted with enough territorial land that I got the impression it is completely left to the tribes. It may technically be "under federal jurisdiction" but if a treaty ceded any or most right to law enforcement then it's independent.
