Who Is a U.S. Citizen?

There are only two ways to become a U.S. citizen: by birth, or through naturalization. The rules for each are more specific, and in places more contested, than that simple split suggests.

Citizenship by birth

The Fourteenth Amendment establishes birthright citizenship directly: anyone born in the United States and subject to its jurisdiction is automatically a citizen, regardless of their parents’ immigration status. This principle, called jus soli (“right of the soil”), was confirmed by the Supreme Court in United States v. Wong Kim Ark (1898), which held that a child born in the U.S. to Chinese immigrant parents who were themselves ineligible for citizenship under the law at the time was still a citizen by birth. Citizenship can also pass through a parent under certain conditions even when a child is born abroad (jus sanguinis, “right of blood”), governed by a separate, more detailed set of federal statutes depending on the parents’ own citizenship and residency history.

Citizenship by naturalization

Naturalization is the legal process by which a non-citizen becomes a citizen, generally requiring lawful permanent residency (a green card) for a set number of years, continuous residence and physical presence requirements, an English language and civics test, and an oath of allegiance to the United States. Congress holds constitutional authority over naturalization rules directly (Article I gives Congress power over “an uniform Rule of Naturalization”), which is why the specific requirements have changed multiple times throughout American history as Congress has revised the underlying statutes.

Worth knowing

Birthright citizenship has become a genuinely contested legal question in recent years specifically regarding children born to parents who are in the country without legal authorization. The debate centers on how to read the Fourteenth Amendment’s phrase “subject to the jurisdiction thereof” - whether it excludes children of undocumented immigrants, an interpretation most legal scholars and over a century of settled practice have rejected, though the question has recently drawn renewed political and legal attention.

Why it still matters

Citizenship status determines who can vote in federal elections, hold most federal offices, obtain a U.S. passport, and remain in the country without risk of deportation - it’s the legal foundation underneath nearly every other question of political participation this site covers.