The word treaty has been used for more than 600 years to convey a sense of negotiated agreement between two parties with the power to make a promise and keep it. But an agreement is only as strong as each party’s willingness and ability to keep their promises. In the First Fort Laramie Treaty of 1851, the United States promised the Cheyenne, Sioux, Arapaho, Crow, Assiniboine, Mandan, Hidatsa, and Arikara Nations that the great plains “as far as the river flows and the eagle flies” was Native ...