The Interior Department held the Chickasaws and other prominent gambling tribes to an easier standard when examining trust land applications, attorney Richard Grellner said.

Meanwhile, smaller tribes with little political clout were held to a much tougher legal standard, Grellner claimed. For instance, the smaller tribes were required to state on trust land applications whether they intended to build a casino. The impact of Russell's ruling is unclear. Attorneys said it's doubtful that tribes will be forced to close casinos already built at those locations.

The Marlow location, like the sites of numerous other Oklahoma casinos, was placed in trust after October 1988. Under the Indian Gaming Regulatory Act of 1988, that means the land is supposed to receive tougher scrutiny by the Interior Department.

The Chickasaws claimed the Marlow property was part of their "former reservation" and thereby exempt from the tougher rules. The Interior Department agreed and made the land legal for gambling.

Russell said there was insufficient evidence to support that claim. He ordered the Interior Department and the National Indian Gaming Commission to determine whether the Marlow property meets the definition of "Indian land" and to justify its reasoning.