Congress' plenary power
The plenary power principle states that Congress has very broad authority in Indian affairs.The Supreme Court has held that this power originates in the Interstate/lndian Commerce Clause of the Constitution, which grants Congress power, “[t]o regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes” (US Constitution Article 1, Section 8, cl. 3: online). According to the Court, this Clause “provides Congress with plenary power to legislate in the field of Indian affairs ...” (US Supreme Court 1989: 192 online).This authority allows Congress to enact laws that injure Indian nations and their citizens or laws that benefit Indigenous tribes and their citizens. Thus, Congress has a nearly unchecked power in Indian affairs. In fact, no federal law regarding Indian nations and Indian peoples has ever been overturned because Congress exceeded its power in the Indian law arena. As a matter of fact, only in recent times did the Supreme Court decide that congressional actions regarding Indian nations can even be reviewed by the courts.
The Executive and Legislative branches of the federal government have guardian and fiduciary responsibilities for American Indian nations. This duty is partially based on the United States nearly unchecked plenary power over Indians and their governments. Principles of general trust law, and the alleged helplessness of tribal nations, led to the rise of the trust responsibility as a corollary to plenary power. In exercising this extremely broad authority, Congress and the Executive Branch are charged with the responsibilities of a guardian to act on behalf of dependent Indian peoples and their governments. The United States has accepted this responsibility and has “charged itself with moral obligations of the highest responsibility and trust” and judges its own conduct towards tribes, “by the most exacting fiduciary standards” (US Supreme Court 1942: online).
The idea of a trust duty began developing in Supreme Court case law in 1831 when the Court considered the sovereign status of the Cherokee Nation. In that case, the Court stated that the Nation was dependent on the United States for its “protection” and “wants” and was in a “state of pupilage” with the federal government. The Cherokee Nation Court then went on to state that the Nation s “relation to the United States resembles that of a ward to his guardian” (US Reports, Cherokee Nation v. Georgia 1831: online). Furthermore, in 1886, the Supreme Court stated that because the, “Indian tribes arc the wards of the nation . . . [and] communities dependent on the United States” that a heavy responsibility weighs on the United States to care for Indians and their governments due to their very, “weakness and helplessness” (US Supreme Court 1886: online).
The idea of a Euro-American duty to ‘protect’ Indians and Indigenous nations arose long before these Supreme Court cases. Euro-Americans had long claimed an obligation to care for the best interests of Indians. Many of the US treaties with Indian nations, for example, contained promises by the United States to protect tribes, to support their commercial activities, and to provide education and medical care (Miller 2006: 25—9,165—6; Laws of the Colonial and State Governments Relating to Indians and Indian Affairs, From 1633 to 1831 1978: 12, 16—17,22, 37,45,59,136,142,146,150,154).
Diminished tribal sovereignty
The third principle, called diminished tribal sovereignty, holds that Indian governmental sovereignty was automatically and immediately diminished upon contact with Euro-Americans. Some Indigenous sovereign rights were automatically diminished under the Doctrine of Discovery as discussed above. But the Supreme Court added two factors that also diminish Indigenous sovereignty even beyond the impact of Discovery. First, the Court implied in Worcester in 1832 that Indian nations could voluntarily give up aspects of their inherent sovereignty and sell land through treaties. Second, the Court has held that Congress can take aspects of Indigenous sovereignty without tribal consent pursuant to its plenary power (Newton, Cohen, and Anderson 2012: 23, 229—32; US Reports, Worcester v. the State of Georgia 1832: online).
In 1978, the Supreme Court added a third factor to the principle of diminished tribal sovereignty. In Oliphant v. Suquamish Indian Tribe, the Court held that the inherent sovereign powers of Indian nations did not, could not, include jurisdiction to criminally prosecute non-lndians.The Court stated that Indian nations could not have this jurisdiction because it would be, “inconsistent with their status”. The Court thus expanded the definition of the diminished sovereignty principle by holding that tribal nations retain those aspects of their inherent sovereignty that they have not voluntarily given up, by treaty for example, or which Congress has not taken, pursuant to its plenary power, or, which they have not impliedly lost by virtue of their dependent status upon the United States (US Supreme Court 1978a: online).
All of these principles of Indian law limit Indigenous sovereignty.