dual citizenship

Multiple citizenship (or multiple nationality) is a person's legal status in which the person is at the one time recognized by more than one country under its nationality and citizenship law as a national or citizen of that country. There is no international convention which determines the nationality or citizenship status of a person, which is consequently determined exclusively under national laws, that often conflict with each other, thus allowing for multiple citizenship situations to arise.
A person holding multiple citizenship is, generally, entitled to the rights of citizenship in each country whose citizenship they are holding (such as right to a passport, right to enter the country, right to work, right to own property, right to vote, etc.) but may also be subject to obligations of citizenship (such as a potential obligation for national service, becoming subject to taxation on worldwide income, etc.).
Some countries do not permit dual citizenship or only do in certain cases (e.g., inheriting multiple nationalities at birth). This may be by requiring an applicant for naturalization to renounce all existing citizenship, by withdrawing its citizenship from someone who voluntarily acquires another citizenship, or by other devices. Some countries permit a renunciation of citizenship, while others do not. Some countries permit a general dual citizenship while others permit dual citizenship but only of a limited number of countries.
A country that allows dual citizenship may still not recognize the other citizenship of its nationals within its own territory (e.g., in relation to entry into the country, national service, duty to vote, etc.). Similarly, it may not permit consular access by another country for a person who is also its national. Some countries prohibit dual citizenship holders from serving in their armed forces or on police forces or holding certain public offices.

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