Article I, Section 8, Clause 4:
[The Congress shall have Power . . .] To establish an uniform Rule of Naturalization, and uniform Laws on the subject of Bankruptcies throughout the United States; . . .
The first sentence of § 1 of the Fourteenth Amendment contemplates two sources of citizenship and two only: birth and naturalization. 1 This contemplation is given statutory expression in § 301 of the Immigration and Nationality Act of 1952, 2 which itemizes those categories of persons who are citizens of the United States at birth; all other persons in order to become citizens must pass through the naturalization process. The first category merely tracks the language of the first sentence of § 1 of the Fourteenth Amendment in declaring that all persons born in the United States and subject to the jurisdiction thereof are citizens by birth. 3 But there are six other categories of citizens by birth. They are: (2)
a person born in the United States to a member of an Indian, Eskimo, Aleutian, or other aboriginal tribe, (3) a person born outside the United States of citizen parents one of whom has been resident in the United States, (4) a person born outside the United States of one citizen parent who has been continuously resident in the United States for one year prior to the birth and of a parent who is a national but not a citizen, (5) a person born in an outlying possession of the United States of one citizen parent who has been continuously resident in the United States or an outlying possession for one year prior to the birth, (6) a person of unknown parentage found in the United States while under the age of five unless prior to his twenty-first birthday he is shown not to have been born in the United States, and (7) a person born outside the United States of an alien parent and a citizen parent who has been resident in the United States for a period of ten years, provided the person is to lose his citizenship unless he resides continuously in the United States for a period of five years between his fourteenth and twenty-eighth birthdays. 4
Subsection (7) citizens must satisfy the condition subsequent of five years continuous residence within the United States between the ages of fourteen and twenty-eight, a requirement held to be constitutional, 5 which means in effect that for constitutional purposes, according to the prevailing interpretation, there is a difference between persons born or naturalized in, that is, within, the United States and persons born outside the confines of the United States who are statutorily made citizens. 6 The principal difference is that the former persons may not be involuntarily expatriated whereas the latter may be, subject only to due process protections. 7