Washington — The Supreme Court on Thursday ruled against the Navajo Nation in a legal dispute involving water access for the tribe, finding a 1868 treaty does not require the United States to take affirmative steps to secure water for the Navajo.

The court divided 5-4 in its decision dismissing the suit brought by the Navajo Tribe against the U.S., with Justice Neil Gorsuch joining with the liberal wing of the bench in dissent.

Writing for the majority, Justice Brett Kavanaugh pointed to the text and history of a 1868 peace treaty agreed to by the U.S. and Navajo Nation, which established the Navajo Reservation, to hold that the agreement does not require the U.S. to undergo efforts to secure water for the Navajos, like assessing the tribe's water needs, crafting a plan to secure the water that is needed and potentially building water infrastructure.

"The 1868 treaty reserved necessary water to accomplish the purpose of the Navajo Reservation," he said. "But the treaty did not require the United States to take affirmative steps to secure water for the Tribe."

Joining Kavanaugh's opinion were Chief Justice John Roberts and Justices Clarence Thomas, Samuel Alito and Amy Coney Barrett.

But Gorsuch, in a dissenting opinion joined by Justices Sonia Sotomayor, Elena Kagan and Ketanji Brown Jackson, said the majority rejected a request that the Navajo Nation never made. Rather than seeking to compel the U.S. government to take affirmative steps to secure water for the tribe, the conservative justice said the tribe has a "simple ask": for the U.S. to identify the water rights it holds for them.

"Where do the Navajo go from here?" Gorsuch wrote. "To date, their efforts to find out what water rights the United States holds for them have produced an experience familiar to any American who has spent time at the Department of Motor Vehicles. The Navajo have waited patiently for someone, anyone, to help them, only to be told (repeatedly) that they have been standing in the wrong line and must try another."

Noting the repeated attempts by the Navajo for the U.S. to provide an accounting of the water rights it holds on the tribe's behalf, Gorsuch said their protracted efforts stretch back to when "Elvis was still making his rounds on the Ed Sullivan Show."

The Navajo Reservation, which has a western boundary that runs along part of the Colorado River, is the largest Native American reservation in the U.S., encompassing more than 17 million acres. Of the tribe's more than 300,000 members, roughly 170,000 live on the reservation. 

Despite lying largely within the Colorado River Basin, water is scarce, and up to 91% of Navajo households on some parts of the reservation lack access to water, according to court papers.

During oral arguments in March, the Biden administration told the court that the U.S. has taken numerous steps to help the Navajo Tribe with its water needs, including securing hundreds of thousands of acre-feet of water and approving billions of dollars for water infrastructure on the reservation.

But the Navajo argued these actions failed to satisfy the government's obligations under the 1868 treaty and, in 2003, sued U.S. agencies. The tribe sought to compel the U.S. government to determine the water required to meet the needs of the Navajo Nation's lands in Arizona and come up with a plan to fulfill those needs, pursuant to the 1868 treaty. 

Several states — Arizona, Nevada and Colorado — intervened against the tribe to protect their interests in water from the Colorado River. 

A federal district court in Arizona dismissed the suit brought by the Navajo Tribe, finding that the 1868 treaty didn't require the U.S. to take affirmative steps to secure water for the tribe. But the U.S. Court of Appeals for the 9th Circuit reversed, holding that the U.S. has a duty to take action to secure the water needed for the reservation and allowing the suit to proceed.

In his opinion, Kavanaugh said while the treaty required the U.S. to build schools, a chapel, and carpenter and blacksmith shops on the reservation, and mandated the government provide teachers for Navajo schools for at least 10 years, it "said nothing about any affirmative duty for the United States to secure water."

"Of course, it is not surprising that a treaty ratified in 1868 did not envision and provide for all of the Navajos' current water needs 155 years later, in 2023," he said. "Under the Constitution's separation of powers, Congress and the President may update the law to meet modern policy priorities and needs. To that end, Congress may enact — and often has enacted — legislation to address the modern water needs of Americans, including the Navajos, in the West."

Gorsuch, though, said the promise of a "permanent home" extended in the 1868 treaty secures "some measure" of water rights for the Navajo.

"The government owes the Tribe a duty to manage the water it holds for the Tribe in a legally responsible manner," he wrote in dissent. "In this lawsuit, the Navajo ask the United States to fulfill part of that duty by assessing what water rights it holds for them. The government owes the Tribe at least that much."