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.
Tanzanian nationality law
Tanzania does not currently allow its citizens to hold foreign citizenship in addition to their Tanzanian citizenship, except in the case of Tanzanian woman acquiring foreign nationality through marriage, or persons under 18 who acquire Tanzanian citizenship by birth or descent. Multiple nationals automatically lose their Tanzanian citizenship at 18 unless they renounce all other citizenships. The ban on dual citizenship has historically been motivated by suspicions about potential disloyalty amongst the sizable Asian minority. Nevertheless, a debate has arisen about permitting dual citizenship. In August 2007, the minister of home affairs submitted a report recommending that the law be changed. Nevertheless, Tanzania currently continues to restrict dual citizenship.