The court of appeals affirmed in part, reversed in part and dismissed in part a circuit court judgment. The court held that a district court’s denial of a tribal sovereign immunity claim is appealable on an interlocutory basis as a collateral order.

The Burlington Northern & Santa Fe Railway Company (BNSF) brought suit against two officials of the Hualapai Indian Tribe, Charles Vaughn and Wanda Easter. The railway company sought declaratory and injunctive relief against the tribal officials’ efforts to enforce or collect the Hualapai Tribe’s possessory interest tax against BNSF for use of the railroad’s right-of-way through the reservation.