Here is the opinion.

Briefs here.

An excerpt:

We begin by discussing the tribal exhaustion doctrine involved in this case. “[W]hen a federal court has subject-matter jurisdiction over a claim arising in Indian country over which a tribal forum has colorable jurisdiction, principles of comity and the federal policy of promoting tribal self-government generally require that the plaintiff fully exhaust tribal remedies before proceeding in federal court.” Restatement of the Law of Am. Indians § 59 cmt. a (Am. Law Inst., Proposed Final Draft 2021).

slip op. at 14.

Maybe a little more Restatement. . . .

Post–Santa Clara Pueblo, federal review has been limited to habeas, leaving tribal courts to adjudicate any other civil rights claims. See Restatement of the Law of Am. Indians § 16 cmt. a (“With the exception of actions for habeas corpus relief [under § 1303, ICRA’s civil rights] guarantees are enforceable exclusively in tribal courts and other tribal fora.”).

slip op. at 21.

And more. . . .

Tribal exhaustion doctrine exists to preserve tribal sovereignty and prevent the federal courts from running roughshod over tribal legal systems. See Norton, 862 F.3d at 1243; Restatement of the Law of Am. Indians § 28 cmt. a (“[A]djudication of matters impairing reservation affairs by any nontribal court . . . infringes upon tribal law-making authority, because tribal courts are best qualified to interpret and apply tribal law.”).

Slip op. at 34.