Dual nationality occurs when one person becomes a citizen or national of two different countries. The United States does not recognize dual nationality in its statutes, and does not encourage U.S. citizens to attain or maintain dual nationality status, due to problems of allegiance and the practical application of its laws on U.S. citizens living abroad. Despite the unofficial negative position of the United States, dual nationality is in actuality very common, especially among people who attained U.S. citizenship by naturalization or by being born in the United States to parents of foreign nationality.
Acquisition of Dual Nationality
At Birth. Dual nationality is typically acquired at birth when the principles of jus soli and jus sanguinis both apply simultaneously. Jus soli (Latin for “right of soil”) is the principle that a person is conferred citizenship of a country by virtue of being born within the country’s borders. Jus sanguinis (Latin for “right of blood”) is the principle that a person is conferred citizenship by virtue of being born to parents who are citizens of a particular country. Each country has its own rules pertaining to acquisition of nationality, which are usually some variation of jus soli and/or jus sanguinis. So, for example, a person born in the United States to parents who are citizens of Mexico is automatically a citizen of the United States (by jus soli) and a citizen of Mexico (by jus sanguinis). Likewise, a person born in Mexico to parents who are citizens of the United States would be automatically a citizen of both countries.
By naturalization. A person may also acquire dual nationality by naturalizing in the United States when the person is already a citizen of another country. It is important to note, however, that naturalizing in the United States could lead to expatriation from the other country of citizenship. This is because one requirement of naturalization in the United States is that the petitioner take an oath renouncing citizenship and allegiance to all other countries. Whether this oath is enough to result in expatriation depends on the other country’s expatriation laws. Note that such an oath taken by a U.S. citizen in a foreign country would in fact be sufficient to result in expatriation from the United States. The acquisition of dual nationality in this situation is thus dependent on the expatriation laws of the other country.
Children under the age of eighteen also may become U.S. citizens automatically if their parent becomes a U.S. citizen through naturalization.
Maintaining Dual Nationality: Avoiding Expatriation
U.S. citizens should be careful if they desire to attain dual nationality. In some instances, attaining dual nationality can result in expatriation from the United States. Expatriation is the concept of relinquishing one’s nationality. One manner of effectuating expatriation is to apply for citizenship in a foreign country if you are already a U.S. citizen. Essentially, when a U.S. citizen applies voluntarily for citizenship in a foreign country, with the intent to give up U.S. citizenship, he or she will be subject to expatriation.
It is worth noting, however, that some cases create no problem, such as when a U.S. citizen marries a foreign national and attains naturalization in their spouse’s country automatically because of the marriage.
Expatriation may also occur in other situations in which a person attempts to exercise the benefits of citizenship in a foreign country, such as voting in an election, taking oath of allegiance, or being employed in a policy-level government position. For a more detailed discussion of expatriation and acts which result in expatriation, see the article on expatriation