Citizenship of the United States
A person who is considered a citizen by more than one nation has "dual citizenship". It is possible for a United States citizen to have dual citizenship; this can be achieved in various ways, such as by birth in the United States to a parent who is a citizen of a foreign country (or in certain circumstances the foreign nationality may be transmitted even by a grandparent) by birth in another country to a parent(s) who is/are a United States citizen/s, or by having parents who are citizens of different countries. Anyone who becomes a naturalized U.S. citizen is required to renounce any prior "allegiance" to other countries during the naturalization ceremony; however, this renunciation of allegiance renunciation of citizenship to those countries.
Afroyim v. Rusk
Afroyim v. Rusk, 387 U.S. 253 (1967), is a major United States Supreme Court case in which the Court ruled that citizens of the United States may not be deprived of their citizenship involuntarily. The U.S. government had attempted to revoke the citizenship of Beys Afroyim, a man born in Poland, because he had cast a vote in an Israeli election after becoming a naturalized U.S. citizen. The Supreme Court decided that Afroyim's right to retain his citizenship was guaranteed by the Citizenship Clause of the Fourteenth Amendment to the Constitution. In so doing, the Court struck down a federal law mandating loss of U.S. citizenship for voting in a foreign election—thereby overruling one of its own precedents, "Perez v. Brownell" (1958), in which it had upheld loss of citizenship under similar circumstances less than a decade earlier.