Here is the opinion in United Planners Financial Services of America v. Sac and Fox Nation:

Order APL-12-01

An excerpt:

There is nothing in the record indicating that the Business Committee met, voted, and approved by resolution or otherwise any specific arbitration clause with Broker or approved any broker agreement, by reference to a specific agreement, which contained an arbitration clause. We do not find any error with the District Court’s finding that authorized representatives of the Nation did execute the broker agreements with Broker. This is because certain officials of the Nation were authorized by resolution to “sell, assign and endorse for transfer, certificates representing stocks, bonds, or other securities now registered or hereafter registered in the name of this corporation.” (App. Rec. at 85-88). But this general approval to engage in broker activities does not rise to the level of an express approval of any arbitration clause or waiver of tribal sovereign immunity. Thus, while we find that the broker agreements were validly approved by the Nation, we do not find valid approval of the arbitration clause that would subject the Nation to be compelled to arbitrate.