From Lakota America: A New History of Indigenous Power, by Pekka Hämäläinen (The Lamar Series in Western History; Yale U. Press, 2019), Kindle pp. 374-375:
The army’s withdrawal only opened the door for another assault by the federal government, now in the form of assertive agents, missionaries, school teachers, and “civilization” programs. The agents no longer sought to reform the Lakota society; that policy had expired the moment Custer died. They now aimed to hollow out Lakota society and fill the void with white American values, norms, words, customs, and thoughts. Once tribalism was pulverized, so went the logic, Lakotas could be absorbed into the American society as individuals and nuclear families.
Some Lakotas accepted and actively embraced farming and schools, but most were horrified by the assimilationist zeal. After all, Lakotas had possessed an extensive reservation and dominated the vast northern plains only a year earlier; their fall from power had been shockingly fast and complete. The acreage under the plow increased across the reduced reservation, but so too did resentment and despair. Chiefs struggled to maintain their status in a strange world where government agents incited rivalries among them, mobilized the akíčhitas [= marshals, camp police] to control them, and withheld rations to weaken them. Former hunters and warriors were reduced to eking out a living by driving wagons, hauling freight, and cutting wood. Women’s traditional roles narrowed in the male-dominated reservation milieu and their standing as providers deteriorated as men took up farming and secured wage jobs. Children were removed from their families and taken to boarding schools where, separated from what was traditional and safe, they received an education geared to extinguish the Lakota culture.
The Great Sioux Reservation became a battleground for competing visions of the Lakota future. In 1881 Spotted Tail was killed by Crow Dog, a captain of the Indian police, who could not accept the old chief’s defiant traditionalism, persisting popularity, and multiple wives. That same year Sitting Bull, no longer able to hold on to his starving followers, crossed the medicine line [Canadian border] again and formally surrendered at Fort Buford with Crow King. He gave his rifle to his six-year-old son who handed it over to an army officer. “I wish it to be remembered that I was the last man of my tribe to surrender my rifle,” the fifty-year-old chief said. “This boy has given it to you, and now wants to know how he is going to make a living,” he said, intimating the struggles his son and others of his generation would face in the alien world the wašíčus [whites] imposed on the Lakotas. Crow King asked a Chicago Tribune correspondent for two dollars to buy dolls for his girls.
Sitting Bull was taken to Fort Randall on the Missouri River where he was held as a prisoner of war for nearly two years. He then settled in the Standing Rock Agency where James McLaughlin, a ruthlessly effective assimilation crusader, was tearing the fabric of the Lakota society apart by recruiting “boss” farmers, policemen, and judges among the Lakotas to educate, monitor, and punish other Lakotas. The rift between the Indian police and traditional spiritual leaders became particularly corrosive.