The Supreme Court ruled Thursday in a 5-4 vote that a large part of Oklahoma remains a Native American reservation, with Justice Gorsuch authoring the majority opinion.

The issue before the court was whether the eastern half of Oklahoma is a Native American reservation, which would be exempt from local and state control.

Jimcy McGirt, a Native American man who was convicted of sex crimes against a child in Oklahoma state court, went before the Court. He argued that because he is a member of the Muscogee (Creek) Nation and the alleged crime took place on tribal land, he is not subject to the jurisdiction of local and state courts. Instead, he claimed to be subject to Creek Nation’s jurisdiction and federal jurisdiction.

Oklahoma argued that land must be “reserved from sale” to be considered a reservation. The Court disagreed, relying on the 1833 treaty that promised a permanent home for the Creek Nation, “so long as they shall exist as a nation, and continue to occupy the country hereby assigned to them.” An 1866 treaty later promised the Creek Nation the right of self-government.

Once a treaty establishes a reservation, only Congress can alter it. The Court found that Congress did not eliminate the reservation.

Justice Gorsuch wrote:

The federal government promised the Creek a reservation in perpetuity. Over time, Congress has diminished that reservation. It has sometimes restricted and other times expanded the Tribe’s authority. But Congress has never withdrawn the promised reservation. As a result, many of the arguments before us today follow a sadly familiar pattern.

Continuing, Justice Gorsuch claimed the pattern of unkept promises needs to end and reminded the court, “If Congress wishes to withdraw its promises, it must say so.”

Justice Roberts filed a dissenting opinion, which Justices Alito, Thomas, and Kavanaugh joined. Justice Thomas also filed a separate dissent.