SOVEREIGNTY AND INDIAN CASINOS
Indian tribes are "distinct, independent political communities, retaining their original natural rights" in matters of local self-government.
The opinions of federal and state courts are persuasive authority, but tribal judges are not bound by such precedents.
Like other sovereign governmental entities, tribes enjoy common law sovereign immunity and cannot be sued: An Indian tribe is subject to suit only where Congress has "unequivocally" authorized the suit or the tribe has "clearly" waived its immunity.
Tribes are also immune from the enforcement of a subpoena, e.g., to compel production of documents.
If a tribe is immune from state or federal suit, documents exchanged between tribes and DOI or BIA regarding "tribal interests" or "matters internal to the tribe," are exempt from disclosure under FOIA.
Tribes retain immunity from suit when conducting business transactions both on and off the reservation.
A contractual agreement to arbitrate disputes constitutes a clear waiver of immunity.
You probably can't sue a Tribe for Employment Discrimination.
Similarly, the Ninth Circuit has held that tribes are immune from suit under the Age Discrimination in Employment Act. Tribes are also immune from suit under 42 U.S.C. Section 1983.
Likewise, state discrimination laws do not apply to tribal employers.
A court cannot compel a tribe --- or the Bureau of Indian Affairs --- to provide documents about the tribe's employment practices, i.e., matters "internal" to the tribe.