Winters v. United States

By a 8-1 decision, the Court found in favor of the U.S. government. Justice Joseph McKenna, writing for the majority, found that the key factor was the 1888 agreement creating the Fort Belknap Indian Reservation. McKenna found it unnecessary to determine the validity of Winter's water right claim because when the Fort Belknap land was reserved in 1888, water rights for the Native Americans were reserved as well by implication.

McKenna wrote that the reservation was originally part of a much larger traditional territory the Native Americans rightly occupied. The expansive region was adequate to meet the needs of a nomadic people. However, government policy dictated the Native Americans become a pastoral and westernized people and the Native Americans agreed to change their lifestyle. Consequently, the original territory became larger than necessary but a smaller tract would be inadequate without changing its condition. The arid lands without irrigation were not favorable to more permanent settlement.

McKenna acknowledged the difficulty of interpreting implicit elements of agreements. But, a standard established in United States v. Winans (1905) required that interpretation of ambiguities in agreements and treaties between the United States and the Native Americans must be made in favor of the Natives. McKenna found that the Court was faced with two questions. First, did Congress, in creating the Fort Belknap Indian Reservation by agreement, imply a guaranteed reasonable quantity of water to the Native Americans. Secondly, did Congress terminate this reservation of water when it admitted Montana to the Union one year later "upon an equal footing with the original States."

In answering the first question, McKenna emphasized that the reservation was created to change the Native Americans' "nomadic and uncivilized" habits, making them into "a pastoral and civilized people." Without water to irrigate the lands, however, the reservation would be "practically valueless" and "civilized communities could not be established thereon." The fundamental purpose of the reservation would be "impaired or defeated."

Regarding the second question, McKenna wrote,

it would be extreme to believe that within a year Congress destroyed the reservation and took from the Indians the consideration of their grant, leaving them a barren waste - took from them the means of continuing their old habits, yet did not leave them the power to change to new ones.

McKenna, ruling in favor of the United States, found it unreasonable to assume that Native Americans would settle on reservation lands to begin farming and grazing without having the water to successfully pursue those activities. Justice Brewer dissented alone without stating his objections.