The Supreme Court on Thursday ruled against the Navajo Nation over claims that the federal government has failed to assert the tribe's desperate need for water access in the arid West.

The justices, divided 5-4, said a lawsuit the tribe filed against the federal government must be thrown out.

Writing for the majority, Justice Brett Kavanaugh said that an 1868 treaty with the Navajo Nation did not require the U.S. government to take active steps to secure water access.

"And it is not the judiciary's role to rewrite and update this 155-year-old treaty," he added.

Conservative Justice Neil Gorsuch joined the three liberal justices in dissent.

The tribe was merely asking the federal government to identify its water rights and was not seeking dramatic further steps, Gorsuch wrote.

As tribal members have had to do throughout their difficult history, "they must fight again for themselves to secure their homeland and all that must necessarily come with it," he wrote.

Buu Nygren, president of Navajo Nation, said in a statement that although the ruling was disappointing, he was encouraged that four justices sided with the tribe. He pledged to continue efforts to obtain water rights to the lower basin of the Colorado River in Arizona.

"My job as the president of the Navajo Nation is to represent and protect the Navajo people, our land, and our future. The only way to do that is with secure, quantified water rights to the Lower Basin of the Colorado River," Nygren said.

The lack of water and infrastructure to pipe it across the vast reaches of the more than 17 million-acre reservation — larger than the state of West Virginia — which straddles parts of Arizona, New Mexico and Utah, remains one of the biggest challenges facing Navajo leaders.