Native Americans and white Americans had fundamentally different legal systems and ideas. This dichotomy was borne out in the 1880s when Crow Dog, a Brule Sioux medicine man, murdered a chief named Spotted Tail on a reservation in the Dakota Territory. While Crow Dog maintained traditional Sioux values, Spotted Tail had argued for peace and cooperation with the whites. The federal government built a house for Spotted Tail in appreciation of his friendship, allowed him to distribute rations, and even named an Indian agency for him. Spotted Tail's prominence antagonized other Sioux, particularly when he began taking the wives of more-traditional chiefs.

Indian Law and American Law.

Under the unwritten law of the Sioux, a murderer could be exiled from the tribe or the victim's family could kill him unless it agreed to restitution. To avoid further bloodshed, the families of Spotted...