A question commonly asked by U.S. lawful permanent residents who have applied to naturalize is, "After I become a U.S. citizen, can I keep the citizenship of my home country—that is, become a dual citizen?"
The answer depends on two factors:
It would be nice if the U.S. Congress had, at some point, simply spelled out within the Immigration and Nationality Act (I.N.A.) that dual citizenship is allowed by the United States. It hasn't done so. In fact, you won't find any formal or official recognition of dual citizenship as an immigration status.
What's more, the oath of allegiance that immigrants must take in order to become naturalized citizens declares that the immigrant will:
renounce and abjure all allegiance and fidelity to any foreign prince, potentate, state, or sovereignty, of whom or which I have heretofore been a subject or citizen.
That's enough to make anyone think that they must choose between whether to be a citizen of the U.S. or of their home country.
Nevertheless, U.S. practice, as upheld in various court decisions, is to allow dual citizenship. (You can see this on the U.S. State Department's website, for example, where it explains that: "U.S. law does not . . . require a person to choose one citizenship or another.")
The United States will not ask naturalizing citizens to take any steps to formally renounce the citizenship of their home country. Nor will it stop U.S. citizens from later adopting citizenship in another country – though if their intention is to give up U.S. citizenship, they can certainly do so. You may continue to vote in your home country, if it allows it.
All this does not mean that the U.S. will tolerate divided loyalties. Dual citizens must obey U.S. laws, uphold the U.S. Constitution, and in every other way adhere to the naturalization oath that they take. They are also required by the I.N.A. to carry their U.S. passport when leaving the U.S., and to present it upon reentry. (I.N.A. Section § 215(b), 8 U.S.C. § 1185(b).)
What the U.S. government says or does about dual citizenship is only half the inquiry. If your home country forbids this practice, then becoming a naturalized U.S. citizen will result in the loss of your original citizenship.
The various countries' laws on dual citizenship change frequently, so your best bet is to get in touch with your country's consulate within the U.S. and find out its latest stand on the matter.
The answer you receive may not be a straightforward "yes" or "no." You may, for instance, need to formally apply to your home country's government in order to maintain citizenship there before you become a U.S. citizen. (So be sure to check on this matter well in advance of your naturalization ceremony!)
For more information, consult an experienced U.S. immigration attorney—and possibly an attorney in your home country, given that U.S. attorneys are not always familiar with other countries' citizenship laws. Also, continue reading to learn more about your rights and benefits as a new U.S. citizen.