The first official written explanation of American citizenship was included in the 14th Amendment to the Constitution (1868). Section 1 of this amendment declares that "All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside." The wording of this amendment places national citizenship before state citizenship. In other words, an American is first a citizen of the United States and then a citizen of the state in which he or she lives. Citizens are entitled to the rights granted by both the national government and their own state's government.
The 14th Amendment was passed to guarantee citizenship to blacks who were freed from slavery after the Civil War (13th Amendment, 1865). The amendment made the rule of jus soli (place of birth) a law for all U.S. citizens. This means that any child born in the United States becomes a citizen at birth, even if its parents are aliens. (However, the rule does not apply to children born to foreign diplomats or United Nations officials.)
The 14th Amendment does not include jus sanguinis. American citizenship acquired at birth in a foreign nation is usually determined by the law that is in effect at the time the child is born. The Immigration and Nationality Act of 1952, amended in 1965, 1976, and 1978, gives the requirements.
For a child born on or after December 24, 1952, both parents must have been American citizens. In addition, one parent must have lived in the United States for ten years (and for at least five years after the age of 14) before the birth of the child.