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In law, a plenary power or plenary authority, derived from the Latin term plenus , 'full'. is a complete and exclusive power over a particular subject matter, with no or minimal substantive limitations, and without needing additional authorization. [1]
Congress and the President have plenary power to make and enforce immigration and nationality policy, with limited judicial review. [2] This power is foregrounded in the "ancient principles of the international law of nation-states", [3] or Ius gentium principles, that immigration and nationality laws are matters of sovereignty; that immigration and naturalization are privileges that exist at the pleasure of the people; and that immigration and nationality laws involve political questions best left to the people. [4] Though this power was largely unused until the 1880s, the underlying principles behind it trace as far back as the Roman Empire and were embraced by Founding Fathers such as Gouverneur Morris, who is quoted as stating: "Every society, from a great nation down to a club, had the right of declaring the conditions on which new members should be admitted." [5] The textual basis of this lies in the foreign affairs powers under the commerce, naturalization, define and punish, and war clauses of the Constitution. [6] [7]
Congress has power over Indian affairs under article I, section 8, clause 3 of the Constitution, or the Commerce Clause: "To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes." [8] The scope of this power is plenary and works to the exclusion of states or tribes, with Congress even able to de-establish a tribe itself. [9] Many tribal leaders view this power over their affairs as tyrannical, since it inhibits self-governance and subjects them to outside forces in Congress. [10]
Congress has power over the postal system under article I, section 8, clause 7, or the Postal Clause: "To establish Post Offices and post Roads." The scope of this power is plenary and is not affected by federalism concerns under the Tenth Amendment. [11]
However, the plenary power doctrine is firmly rooted in the Anglo-American legal tradition. It should be emphasized that the determination to expel or exclude foreigners, whether they have already lawfully settled or even begun the process of naturalization, is a political question and not a vested right absent congressional statutory acquiescence...It is an issue that can only be placed into this nation's political discourse, where it has always and rightfully been.
Stemming from 'ancient principles of the international law of nation-states,' '[t]he power to admit or exclude is a sovereign prerogative.' Indeed, the ability to 'regulate the flow of non-citizens entering the country . . . is an inherent power of any sovereign nation.' This idea traces as far back as the Roman Empire and 'received recognition during the Constitutional Convention.'
Notably, the Constitution does not expressly grant the federal government wholesale foreign affairs power. The foreign affairs power, rather, appears to be an amalgamation of Congress's powers to 'regulate commerce with foreign nations, to define offenses against the law of nations, and to declare war'…One more provision rounds out constitutional support for federal immigration powers: the naturalization provision that grants the federal government the power to 'establish an uniform Rule of Naturalization,' or a law for granting naturalized citizenship.
[Founding era authorities on the law of nations, such as] Pufendorf, Barbeyac, Vattel, Martens, Blackstone, and—more obliquely, Grotius and Burlamaqui— all addressed limits on immigration when writing on the law of nations. These authors consistently recognized the prerogative of governments to impose immigration restrictions. That prerogative was qualified in cases of necessity (for example, a ship being driven by storm onto a foreign shore), and in the cases of exiles and fugitives. As to voluntary immigrants, however, all but Grotius—the earliest of the writers— recognized that the power to restrict was nearly absolute.
Within the field of functions properly promoted by the postal system Congress' power is plenary and whether Congress may deal directly with a situation in that area or not, the Tenth Amendment ought not restrict the power of Congress.