The Navajo Nation could have a slight edge in a case that will weigh heavily on the tribe and its ability to draw more water from the Colorado River.

U.S. Supreme Court justices on Monday heard nearly two hours of oral arguments, the latest development in Arizona v. Navajo Nation, where the tribe claims the U.S. has a “treaty-based duty” to supply the reservation with adequate water.

That argument stems from nearly a century of case law, beginning with Winters v. United States, where in 1908, the Supreme Court ruled the government has an obligation to supply water to tribes confined to a reservation via treaty.

Justices Neil Gorsuch, Ketanji Brown Jackson, Elena Kagan and Sonia Sotomayor all seemed to support the tribe’s claim.

It’s likely Justice Amy Coney Barrett, whose questions hinted at support for the tribe’s ability to pursue a claim to the river, will be the tie-breaking vote, as has been noted by several Supreme Court analysts.

Supreme Court agrees to hear case over the Navajo Nation’s access to the Colorado River
‘A 100-year tragedy’ for tribes in the Colorado River Basin

A ruling is expected by June, and the case could help resolve the Navajo Nation’s claim to Arizona’s allotment of the Colorado River, where it currently does not have a quantified water right. Estimates vary, but it’s believed between 30% to 40% of residents living on the Navajo Nation, the largest reservation in the country, do not have access to running water.

The Biden administration’s assistant to the U.S. Solicitor General Frederick Liu said that while the government is committed to helping the Navajo Nation, “the 1868 treaty didn’t impose on the United States a duty to construct pipelines, pumps, or wells to deliver water.”

Still, the Navajo Nation maintains the federal government has failed to “assess the Navajo Nation’s water needs and develop a plan to meet them,” the tribe said in a statement.

“We honored our end of the deal, and they just need to honor their end of the deal,” Navajo Nation President Buu Nygren said in a statement Tuesday.

Buu Nygren leads the nation

While their five colleagues appeared sympathetic to that argument, Chief Justice John G. Roberts Jr. and Justices Clarence Thomas, Samuel A. Alito Jr. and Brett M. Kavanaugh were skeptical.

“Congress has shown the ability to do this with other tribes and other reservations and that rather than a multiyear journey here, where, really, it’s not clear you can ever get what you really want out of the court system, as we’ve danced around today, we should leave it to Congress,” Kavanaugh said, summing up what he said is the solicitor general’s stance on the matter in a question to the tribe’s lawyer, Shay Dvoretzky.

And Thomas seemed to imply that the tribe should consider alternative sources of water, including groundwater, instead of drawing from the already beleaguered Colorado River.

“Have you, throughout this litigation, suggested any other source than the Lower Colorado?” he asked Dvoretzky.

Alito’s concerns stemmed from the existing agreements on the Colorado River, where eight states and Mexico are currently operating on a system of allocation that, amid drought, appears precarious.

“Do you think that you have the right to take out from that water source whatever quantity of water is necessary to meet the standard of a livable, permanent homeland regardless of the needs of others who are drawing water from the same water source?” Alito asked.

“The Nation had water rights first. We do have priority rights to the water,” responded Dvoretsky.

Gorsuch appeared to be the justice most supportive of the Navajo Nation’s claim, telling Liu “there’s some obligation with respect to water in this treaty.”

“Could I bring a good breach-of-contract claim for someone who promised me a permanent home, the right to conduct agriculture and raise animals if it turns out it’s the Sahara Desert?” he asked.

Liu said he didn’t believe there would be a valid breach-of-contract claim, in which Gorsuch responded with skepticism.

And while Barrett came across as the most neutral justice, with some concerns around the idea that the government could be responsible for infrastructure projects, there were moments where she expressed support for the Navajo Nation.

“It seems to me that the strongest arguments made on behalf of the Navajo in the Navajos’s brief are in the nature of you breached the treaty,” she said, “... you promised us a permanent home.”

In attendance were several Navajo leaders, including Nygren, Navajo Nation Vice President Richelle Montoya, and Navajo Speaker Crystalyne Curley.

“This case goes beyond the fiduciary duty of the federal government. The outcome of this hearing may determine the livelihood of our Navajo people now, and for all future generations,” said Curley in a statement to the Deseret News. “The right to water centers on our right to a permanent homeland through our treaties and the prayers of our ancestors since time immemorial. As a child, I grew up in a home without running water and to this day, we still have over 30% of our people who don’t have access to clean running water in their homes. Our leaders long ago fought for our right to our homeland and that includes the right to water, the right to life.”