United States of America - Passport & Nationality - Dual Nationality
The concept of dual nationality means that a person is a citizen of two countries at the same time. Each country has its own citizenship laws based on its own policy. Persons may have dual nationality by automatic operation of different laws rather than by choice. For example, a child born in a foreign country to US citizen parents may be both a US citizen and a citizen of the country of birth.
A US citizen may acquire foreign citizenship by marriage, or a person naturalized as a US citizen may not lose the citizenship of the country of birth. US law does not mention dual nationality or require a person to choose one citizenship or another. Also, a person who is automatically granted another citizenship does not risk losing US citizenship. However, a person who acquires a foreign citizenship by applying for it may lose US citizenship. In order to lose US citizenship, the law requires that the person must apply for the foreign citizenship voluntarily, by free choice, and with the intention to give up US citizenship.
Intent can be shown by the person's statements or conduct. The US Government recognizes that dual nationality exists but does not encourage it as a matter of policy because of the problems it may cause. Claims of other countries on dual national US citizens may conflict with US law, and dual nationality may limit US Government efforts to assist citizens abroad. The country where a dual national is located generally has a stronger claim to that person's allegiance.
However, dual nationals owe allegiance to both the United States and the foreign country. They are required to obey the laws of both countries. Either country has the right to enforce its laws, particularly if the person later travels to that country. Most US citizens, including dual nationals, must use a US passport to enter and leave the United States. Dual nationals may also be required by the foreign country to use its passport to enter and leave that country.
For more specific information about some countries where you hold citizenship:
Under the nationality laws of some countries, a married person automatically has his or her partner's nationality. Children may also have a parent's nationality even if they were born abroad. If your wife, husband or child is visiting the country of your nationality, you should check with the country's consulate or high commission in the United Kingdom before you travel.