Later this month, the Supreme Court will hear a case in which the Colorado River water crisis will collide with centuries old treaties between America and the Navajo Nation. The case, Arizona v. Navajo Nation, hinges on the idea of implied water rights, with the Navajo position being that the American government, in promising the Navajo land for farming, also promised them the water to keep that land arable.

The Navajo argue that treaties signed in 1849 and 1868 that allowed the Navajo to return to their homeland to “raise crops and livestock” also “included a promise to provide the water needed to make their way of life on the Reservation possible.” The tribe is hoping that the high court will answer the question of whether the federal government, based on these treaties, has a duty to “assess the Navajo Nation’s water needs and develop a plan to meet them.”