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.
In 1903, the Court in the Japanese Immigrant Case reviewed the legality of deporting an alien who had lawfully entered the United States, clarifying that an alien who has entered the country, and has become subject in all respects to its jurisdiction, and a part of its population could not be deported without an opportunity to be heard upon the questions involving his right to be and remain in the United States.1 In the decades that followed, the Supreme Court maintained the notion that once an alien lawfully enters and resides in this country he becomes invested with the rights guaranteed by the Constitution to all people within our borders.2
Eventually, the Supreme Court extended these constitutional protections to all aliens within the United States, including those who entered unlawfully, declaring that aliens who have once passed through our gates, even illegally, may be expelled only after proceedings conforming to traditional standards of fairness encompassed in due process of law.3 The Court reasoned that aliens physically present in the United States, regardless of their legal status, are recognized as persons guaranteed due process of law by the Fifth and Fourteenth Amendments.4 Thus, the Court determined, [e]ven one whose presence in this country is unlawful, involuntary, or transitory is entitled to that constitutional protection.5 Accordingly, notwithstanding Congress's indisputably broad power to regulate immigration, fundamental due process requirements notably constrained that power with respect to aliens within the territorial jurisdiction of the United States.6
Yet the Supreme Court has also suggested that the extent of due process protection may vary depending upon [the alien's] status and circumstance.7 In various opinions, the Court has suggested that at least some of the constitutional protections to which an alien is entitled may turn upon whether the alien has been admitted into the United States or developed substantial ties to this country.8 Thus, while the Court has recognized that due process considerations may constrain the Federal Government's exercise of its immigration power, there is some uncertainty regarding the extent to which these constraints apply with regard to aliens within the United States.
constitution.congress.gov
