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.
German passport
The right to hold both a German passport and a foreign passport at the same time (dual citizenship) is restricted under the current German nationality law. Germany allows dual citizenship with other EU countries and Switzerland; dual citizenship with other countries is possible with special permission or if obtained at birth (for example, one German parent and one foreign parent, or if a child is born to German parents in a jus soli country such as the United States of America). Under Article 116 par. 2 of the Basic Law (Grundgesetz), former German citizens who between January 30, 1933, and May 8, 1945, were deprived of their German citizenship on political, racial, or religious grounds may re-invoke their citizenship and the same applies to their descendants, and are permitted to hold dual (or multiple) citizenship.