Colorado River Indian Tribes v. National Indian Gaming Commission

The IGRA created the National Indian Gaming Commission (defendant) with joint regulatory and audit authority over class II gaming (like bingo), while leaving class III gaming (slots, roulette, blackjack) to be governed by tribal-state compact under state-law standards; the Colorado River Indian Tribes (plaintiff) conducted class III gaming under a compact with Arizona. When the Commission later promulgated internal-control standards for both class II and class III gaming and sought to audit the Tribe's class III operations for compliance, the Tribe objected and sued, and the district court held the Commission lacked authority to audit or regulate class III gaming.