United States v. Navajo Nation, 556 U.S. 287 (2009) was a United States Supreme Court case in which the Navajo Nation initiated proceedings in the Court of Federal Claims alleging that when they sought the assistance of the United States Secretary of the Interior to renegotiate their original leasing agreement with the Peabody Coal Company in 1984, a procedural process defined by the 1964 Indian Mineral Leasing Act (IMLA) of 1938, the United States Secretary of the Interior had been improperly influenced by the coal company, and as a result, had breached his fiduciary duty to the Nation when he approved the 1987 lease amendments.

The Court of Federal Claims dismissed the complaint, ruling that although the United States had breached its fiduciary obligations to the Navajo Nation, this breach was not actionable because the United States did not have a trust relationship with the Navajo Nation and monetary relief was not available.

[2] Whether the U.S. may be held liable for a breach of fiduciary duty with an Indian Tribe in connection with the negotiation of a mining lease, even when the U.S. has violated no specific statutory or regulatory duty established in the Indian Mineral Leasing Act of 1938?

[1] The Court ruled that an Indian Tribe must "identify a substantive source of law that establishes specific fiduciary or other duties."

The Court concluded that no provision of the IMLA entitled the tribe to monetary damages as a result of the government's role in the negotiations.