Oklahoma’s prediction that a U.S. Supreme Court ruling for a death row inmate who’s also an American Indian would result in the release of thousands of prisoners is “severely exaggerated,” the Muscogee (Creek) Nation told the justices in a brief today.

The tribe’s filing comes after heated oral argument last month over crime, punishment, and American Indian land that prompted a potentially deadlocked Supreme Court to request more information from the parties to help reach a decision.

The unusual—though not...