Article I, Section 8, Clause 18:

[The Congress shall have Power . . . ] To make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof.

Supreme Court precedent establishes that inherent principles of sovereignty give Congress “plenary power” to regulate immigration. Notwithstanding the implicit nature of this authority, the Court has described the immigration power as perhaps the most complete that Congress possesses.1 The core of this power—the part that has proven most impervious to judicial review—is the authority to determine which aliens may enter the United States and under what conditions. The Court has also established that the executive branch, when enforcing the laws concerning alien entry, has broad authority to do so mostly free from judicial oversight. While the Court has recognized that aliens present within the United States generally have more robust constitutional protections than aliens seeking entry into the country, the Court has upheld federal statutes impacting the rights of aliens within the United States in light of Congress’s unique immigration power, though the degree to which the immigration power is constrained by these constitutional protections remains a matter of continuing uncertainty.

Footnotes

1

Fiallo v. Bell, 430 U.S. 787, 792 (1977) ( “This Court has repeatedly emphasized that ‘over no conceivable subject is the legislative power of Congress more complete than it is over’ the admission of aliens.” ) (quoting Oceanic Steam Navigation Co. v. Stranahan, 214 U.S. 320, 339 (1909)); Fong Yue Ting v. United States, 149 U.S. 698, 707 (1893) ( “The right of a nation to expel or deport foreigners . . . is as absolute and unqualified, as the right to prohibit and prevent their entrance into the country.” ).