Whether the Fifth and Sixth Amendment protections governing infamous criminal punishment apply to aliens within the United States.
Holding
Yes. Aliens within the territorial jurisdiction of the United States are persons protected by the Fifth and Sixth Amendments.
Reasoning
The Court distinguished the Government's broad authority over exclusion and deportation from its authority to impose criminal punishment. Although Congress may regulate the admission and expulsion of aliens through executive or subordinate officials, that immigration power does not place aliens outside constitutional safeguards when the Government seeks to punish them for crime.
The Fifth Amendment protects any "person," not merely a citizen. Relying on the principle expressed in Yick Wo v. Hopkins that constitutional protections extend to all persons within territorial jurisdiction regardless of race or nationality, the Court concluded that aliens cannot be held to answer for capital or otherwise infamous crimes without the constitutional procedures required for criminal prosecution.