A Native American hunter from Montana won his case at the Supreme Court on Monday, solidifying treaty rights for the Crow Tribe and overturning a state fine for poaching.

In a 5-4 decision, the court sided with Clayvin Herrera in his appeal of an $8000 fine from Wyoming in 2014 for hunting elk off-season, without a license in the state's Bighorn National Forest.

The decision clarifies court precedent that historical treaty rights between the U.S. government and Native American tribes did not implicitly end when a territory became a state.

Herrera argued that an 1868 treaty between his tribe and the federal government explicitly protected a right to hunt on "unoccupied lands" at any time. Wyoming claimed that the right disappeared when the state entered the union, and when the federal forest land was designated, making it "occupied."

"We disagree," Justice Sonia Sotomayor wrote of Wyoming's argument in the majority opinion. "The Crow Tribe's hunting right survived Wyoming's statehood, and the lands within Bighorn National Forest did not become categorically 'occupied' when set aside as a national reserve."

Sotomayor, who was joined on the opinion by Justices Ruth Bader Ginsburg, Stephen Breyer, Elena Kagan and Neil Gorsuch, invoked the court's precedent that "Congress must clearly express any intent to abrogate Indian treaty rights."

"First, the Wyoming Statehood Act does not show that Congress intended to end the 1868 Treaty hunting right," Sotomayor writes. "Nor is there any evidence in the treaty itself that Congress intended the hunting right to expire at statehood, or that the Crow Tribe would have understood it to do so."

As for whether a national forest constitutes "occupied" land, the majority wrote that the reserve could not be categorically considered such. But they left open the door for Wyoming to argue in lower court that a narrowly defined area in which Herrera was hunting was in fact occupied.

In a dissent, Justices Samuel Alito, John Roberts, Clarence Thomas and Brett Kavanaugh called the majority's reasoning "plainly contrary" to two Supreme Court precedents: an 1896 case which suggested that some Indian treaty rights extinguished with statehood, and a 1995 case which said Crow hunting rights had lapsed.

"This interpretation of the treaty is debatable," Alito wrote of the majority decision. "Even if the court's interpretation of the treaty is correct, its decision will have no effect if the members of the Crow Tribe are bound under the... holding that the hunting right conferred by that treaty is no longer in force."

The majority concluded that a 1999 Native American treaty-rights case "repudiated" and "undercut" the reasoning in the earlier decisions from 1896 and 1995.