Arizona v. Navajo Nation

Arizona v. Navajo Nation clarified the United States’ trust duties to protect tribal water rights under the Winters doctrine and the 1868 Treaty with the Navajo. Under the Winters doctrine, Indian reservations are permanent homes that include an implicit reservation of water rights. However, Winters did not elaborate on the United States’ role in securing those rights. In Navajo Nation, the Court settled whether the United States has an implied duty under its trust obligations to take affirmative steps in securing water rights for tribes; the Court held no such implied duty exists.