Here is today’s opinion in StoreVisions v. Omaha Tribe (as first reported in Indianz).
An excerpt:
As noted, this separate waiver was signed in the presence offive of the seven members of the tribal council and lends even more weight to an appearance that the signatories to the document—the chairman and vice chairman—were vested with theauthority to waive the tribe’s sovereign immunity.
The court refused to take judicial notice of tribal laws for some reason, and gave great weight to the mere presence of tribal council members in finding a waiver. Fairly remarkable decision.
Turtle Talk 
Not having time to research the issue, I am left wondering how a basically equitable principle like “apparent” authority can be applied to a sovereignty issue. Sovereignty is absolute unless it is actually–by lawful constitutional action–waived. For instance, to maintain waiver against the State, a person has to show that the Nebraska Constitution was followed–i.e. the legislature properly convened and lawfully passed a law waiving immunity. The Governor acting in view of a group of approving legislators when doing something is not a constitutional act of waiver. Why is it different for Indians?