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The federal Indian trust responsibility is a legal obligation under which the United States “has charged itself with moral obligations of the highest responsibility and trust” toward Indian tribes (Seminole Nation v. United States, 1942). This obligation was first discussed by Chief Justice John Marshall in Cherokee Nation v. Georgia (1831). Over the years, the trust doctrine has been at the center of numerous other Supreme Court cases, thus making it one of the most important principles in federal Indian law.
The federal Indian trust responsibility is also a legally enforceable fiduciary obligation on the part of the United States to protect tribal treaty rights, lands, assets, and resources, as well as a duty to carry out the mandates of federal law with respect to American Indian and Alaska Native tribes and villages. In several cases discussing the trust responsibility, the Supreme Court has used language suggesting that it entails legal duties, moral obligations, and the fulfillment of understandings and expectations that have arisen over the entire course of the relationship between the United States and the federally recognized tribes.