Were the Reconstruction Treaties harmful or beneficial to Native Americans?

The Reconstruction Treaties were largely harmful to Native Americans. During the Civil War, federal troops left the Indian Territory, where the Five Civilized Tribes lived, allowing the territory to be taken over by the Confederacy. As a result, the Five Civilized Tribes were basically forced to sign treaties with the Confederacy. After the Civil War, the U.S. government punished the tribes for siding with the Confederacy, though in reality, some members of the Five Civilized Tribes had supported the Union during the war. 

During treaty negotiations, which started in 1865 and concluded in 1866, the Five Civilized Tribes agreed to abolish slavery and provide freedmen with tribal rights. These sections of the treaties were beneficial to freedmen who lived on Native American territory. In addition, the tribes set up an intra-tribal council, chaired by the superintendent of Indian Affairs. The tribes also had to give up land rights to pave the way for the railroad to cross through Indian Territory. The federal government stated that the tribes' alleged support of the Confederacy had invalidated earlier treaties and land rights that the tribes had. As a result, the tribes lost a great deal of land amounting to one half of current-day Oklahoma. Many whites began settling in Indian Territory, and Native Americans lost a great deal of their power in the area.