Arizona v. Navajo Nation

Background

The Navajo Nation, the United States, and the States of Arizona, Nevada, and Colorado disputed water rights tied to an 1868 treaty that established the Navajo Reservation. The treaty implicitly reserved water needed for the reservation under the Court's Winters doctrine. The Navajo sued the federal government asking it to assess tribal water needs, make a plan, and possibly build pipelines or other infrastructure to secure water. The District Court dismissed that claim, the Ninth Circuit said the United States had a duty to take affirmative steps, and the Supreme Court reviewed the case.

Reasoning

The core question was whether the 1868 treaty required the United States to take affirmative steps to secure water for the Navajo. The Court said the treaty did reserve necessary water but did not contain rights-creating or duty-imposing language that would create a judicially enforceable affirmative duty by the United States. The Court relied on its rule that the federal government only owes enforceable trust duties when a treaty, statute, or regulation expressly accepts them, and noted the treaty did include other express duties such as schools and seeds when intended.

Real world impact

As a result, the Navajo cannot use this treaty to force the federal government to undertake broad water projects or to compel an affirmative federal program. Reserved water rights still exist, but securing infrastructure and allocations is left to Congress, the President, and political processes. The decision may limit tribes' ability to force federal action, while states retain means to protect their Colorado River interests; tribes can still seek intervention or other litigation-based remedies to protect specific water claims.

Dissents or concurrances

Justice Thomas concurred but urged clarity about the meaning of the government's "trust" language. Justice Gorsuch (joined by three Justices) dissented, arguing the Navajo only sought an accounting and a plan, not mandatory infrastructure, and that the United States should be required to identify water rights it holds in trust for the Tribe.