Answer:
On the eve of the Civil War in 1861 the Five Tribes had well-established homes and tribal governments in Indian Territory (I.T.). These five republics were forced to respond to the crisis in the United States when U.S. troops were withdrawn from I.T., leaving them vulnerable to the Confederacy. The tribes had little choice but to enter into agreements with Albert Pike, representative of the Confederate government. The Choctaw and Chickasaw were united in their support of the Confederacy, but the other three tribes either had an almost equal number of troops fighting on both sides or had more on the side of the Union, as was the case of the Cherokee. As the United States drew up the Reconstruction Treaties at the conclusion of the Civil War, it disregarded the fact that some tribe members had supported the Union. With pressure from Kansas and other midwestern states, politicians were determined to retaliate for the tribes' support of the Confederacy.
Step-by-step explanation: