In 1823, Chief Justice John Marshall wrote the first of three cases of key Federal Indian law that affirmed tribal sovereignty and established doctrine of Federal trust responsibility. These laws are known as the Marshall Trilogy and are the foundation for current judicial decisions involving the powers of tribes. Summaries of these cases follow.

Johnson v. M'Intosh, 21 U.S. (8 Wheat) 543 (1823)
This case involved competing claims to the same lands acquired from the same Indian tribe by different means. The court ruled that Indian nations could only convey ownership to the United States and not individuals. This approach restrained encroachment not authorized by the United States into Indian territories and confirmed Federal control of Indian affairs.

Cherokee Nation v. Georgia, 30 U.S. (5 Pet.) 1 (1831)
The Cherokee Nation challenged the legality of the State of Georgia to oust the Cherokee Nation from its lands in spite of its treaty with the United States. Judge Marshall ruled that the Cherokee Tribe is a "domestic dependent nation" with the relation of the tribe to the Federal Government like that of "ward to guardian." Therefore, the State could not interfere with the Cherokee Nation.  (The State of Georgia did not follow the ruling and continued to interfere in the rights of the Cherokee Nation).

Worcester v. Georgia, 31 U.S. (6 Pet.) 515 (1832)
Missionaries to the Cherokee Nation appealed their conviction in Georgian courts for not having received a license from the Governor of Georgia to enter Cherokee country. Judge Marshall ruled the conviction by the State was void because the tribe was a distinct community over which the laws of the State have no force.