The Supreme Court on Thursday dashed the Navajo nation’s hopes for more running water.

The judges, in a 5-4 decision, overturned a lower court ruling that held an 1868 treaty restricting Navajos to their reservation, with an implicit promise that they would have access to water.

Judge Brett M. Kavanaugh said the treaties that established the Navajo reservation contained no such affirmative promise.

Judge Amy Coney Barrett cast a key vote for the majority, while Judge Neil M. Gorsuch disagreed with the court’s three liberals.

The cases are Arizona vs. Navajo Nation and Dept. of the Interior vs. Navajo Nation.

Washington attorney Shay Dvoretsky, who represented the Navajo Nation in a lost case, had argued that the court need not consider the Colorado River at this stage of the case.

Today, the average person on the Navajo reservation consumes only 7 gallons of water per day. The national average is 80 to 100 liters, he said. The nation asks only that the United States, as trustee, assess the needs of its people and develop a plan to meet them.

For more than a decade, the Navajo nation has been fighting its claims for water rights in federal court. It won a preliminary victory in 2021 in the 9th Circuit Court of Appeals, which said it had a breach of trust claim, noting that the 1868 treaty referred to agriculture.

The right of nations to work reservation lands … gives rise to an implied right to the water required to do so, the appeals court said. However, it stopped short of deciding whether this included rights to the Colorado River’s main stream or to other specific water sources.

But last fall, the Supreme Court agreed to hear appeals from both the Interior Department and Arizona seeking to overturn the 9th Circuits decision.

U.S. Solicitor General Elizabeth B. Prelogar argued that the 1868 treaty said nothing about water and did not establish specific obligations for the government regarding water. In addition, the Navajo nation has been granted water rights from two tributaries of the Colorado River, including Utah’s San Juan River, she said.

Lawyers for Arizona, joined by the Metropolitan Water District of Southern California, said the high courts’ decrees have allocated the waters of the lower Colorado River and it is too late for lawsuits seeking new rights to the same water.