[JURIST] The US Supreme Court [official website] ruled [opinion, PDF] 5-4 Tuesday in Michigan v. Bay Mills Indian Community [SCOTUSblog backgrounder] that tribal sovereign immunity bars a state from suing in federal court to enjoin a tribe from violating the Indian Gaming Regulatory Act (IGRA) [25 USC § 2701 et seq.] outside of Indian lands. In this case the state of Michigan and the Little Traverse Bay Bands of Odawa Indians brought suit to prevent the Bay Mills Indian Community from operating a small casino in Vanderbilt, Michigan. The district court entered a preliminary injunction ordering Bay Mills to stop gaming at the Vanderbilt casino. The US Court of Appeals for the Sixth Circuit held [opinion] that the district court lacked jurisdiction over some of the plaintiffs’ claims and that sovereign immunity bars the others. The court affirmed, in an opinion by Justice Elena Kagan:

We hold that immunity protects Bay Mills from this legal action. Congress has not abrogated tribal sovereign immunity from a State’s suit to enjoin gaming off a reservation or other Indian lands. And we decline to revisit our prior decisions holding that, absent such an abrogation (or a waiver), Indian tribes have immunity even when a suit arises from off-reservation commercial activity. Michigan must therefore resort to other mechanisms, including legal actions against the responsible individuals, to resolve this dispute.

Justice Sonia Sotomayor filed a concurring opinion. Justice Antonin Scalia filed a dissenting opinion. Justice Clarence Thomas also filed a dissenting opinion, joined by Justices Scalia, Ruth Bader Gisburg and Samuel Alito.

The court heard oral arguments in December after granting certiorari [JURIST reports] last June. At oral arguments counsel for Michigan argued that “a tribe should not have greater immunity than foreign nations. There’s no dispute that if France opened up an illegal business in Michigan, casino or otherwise, it would have no blanket immunity.” Counsel for the respondents argued that “The proper inquiry for this Court … is it requires an unequivocal expression of purpose of Congress before tribal immunity is abrogated, and we don’t get into this kind of question of what Congress might have thought, which creates a guessing game.” Counsel for the US government argued as amicus curiae on behalf of respondents.