Because the young United States followed British common law, it accepted the rule of jus soli, or place of birth. As early as 1790, Congress recognized the rule of jus sanguinis, or blood relationship, by passing laws giving citizenship to a child born in a foreign country if the father was a citizen of the United States.
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.