The United States Supreme Court case of United States, Ex Rel., Council of Keokuk, was a dispute between the United States and the Council of Keokuk, a Native American tribe. The dispute centered around the tribe's claim to a tract of land in Iowa, which the United States had granted to the tribe in 1836. The United States argued that the tribe had forfeited its claim to the land by failing to occupy it, and that the land had been sold to a third party. The Council of Keokuk argued that the United States had failed to fulfill its treaty obligations to the tribe, and that the tribe had not forfeited its claim to the land. The Supreme Court ultimately sided with the United States, ruling that the tribe had forfeited its claim to the land by failing to occupy it. The Court also held that the United States had fulfilled its treaty obligations to the tribe, and that the land had been sold to a third party. The Court's decision effectively ended the dispute between the United States and the Council of Keokuk, and established the precedent that Native American tribes must occupy their land in order to maintain their claim to it.

In United States, Ex Rel., Council of Keokuk (1867), the Supreme Court was asked to decide whether a treaty between the United States and certain Native American tribes had been violated. The majority opinion held that it had not been violated because Congress did not have authority over Indian affairs at that time. However, in his dissenting opinion Justice Field argued that Congress did indeed have such authority under Article I, Section 8 of the Constitution which gives them power to regulate commerce with foreign nations and among several states as well as with Indian tribes. He further argued that since this particular treaty involved land transactions between two sovereigns -the US government and an Indian tribe- it should be considered a commercial transaction subject to congressional regulation. Therefore he concluded that Congress could pass laws regulating these types of treaties even if they were made before its existence or without its approval.