Gorsuch, J., dissenting
Colorado River waters.” Id., at 560.
Reality never quite caught up to the law’s ambitions. After an agreement among the States failed to emerge and the Secretary began issuing contracts to various users, Arizona in 1952 brought an original action in this Court against California seeking a declaration of its water rights in the Lower Basin. Id., at 550–551. Several other States intervened. Ibid. So did the United States. Ibid. In doing so, the federal government claimed the need to “protect federal interests, including the rights of the Navajo Nation and twenty-four other Indian [T]ribes in the Lower Basin.” App. 104. As the litigation unfolded, however, the Navajo began to worry that the United States did not have their best interests in mind. In 1956, the Navajo Nation sought leave to file (along with six other Tribes) a motion seeking “to define the scope of the representation of the [T]ribes by the United States” and objecting to what they considered a “lack of effective representation and [a] conflict of interest.” Id., at 105. That motion was denied. Ibid.
Proceeding without the Navajo, this Court referred the litigation to a Special Master. In time, the Special Master prepared a report and recommendation that omitted any mention of the Tribe. Ibid. In response, the Navajo wrote to the Attorney General. They asked the United States to object to the Special Master’s report on their behalf. Id., at 105–106. The Navajo say they never received a response. Id., at 106. For its part, the United States eventually did object—but not on the grounds the Navajo sought. Ibid.
Having seen enough, the Navajo in 1961 moved to intervene. Ibid. They “argued that the United States had failed to vigorously assert” their interests. Ibid. More than that, the Tribe contended, the United States had “ ‘abandoned the case so far as the adjudication of the rights of the Navajo Indians [was] concerned.’ ” Ibid. The United States opposed the Tribe’s motion. Ibid. On its view, it had already
