Is dual citizenship legal?
Dual nationality is legal. People who become US citizens don’t automatically give up their previous citizenship. US citizens can keep their citizenship when becoming citizens of another country.
Controlling citizenship is one way a sovereign country controls its territory. Each country gets to choose who is a citizen. Only the United States can say who is and who is not a US citizen. We can’t say someone’s not a citizen somewhere else. If some other country wants to claim you as their citizen, they can.
When a foreign citizen becomes a US citizen, this doesn’t revoke that new US citizen’s old citizenship. Only their home country can do that. Chinese law, for example, automatically revokes the Chinese citizenship of anyone who naturalizes and resides abroad.
Similarly, US citizens, naturalized or natural-born, don’t automatically lose their citizenship by taking a similar oath to gain foreign citizenship. At least with oaths of foreign allegiance, the State Department presumes you didn’t really mean it.
Officially, the State Department says: “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.”
You can do lots of expatriating acts. Expatriating acts are things that can cause you to lose US citizenship,but may not, so long as you don’t have the intention of giving up your United States citizenship.
Here are some acts that could make you lose your citizenship:
- Obtaining naturalization in a foreign state,
- Swearing allegiance to a foreign state, and
- Serving in another country’s armed forces, so long as not engaged in hostilities with the United States.
But, acts alone aren’t enough. You have to really want to turn your back on America and give up your US citizenship, which the State Department does all they can to prevent. They officially and very generously presume that US citizens performing expatriating acts intend to retain US citizenship.
You basically have to renounce your US citizenship. But if you do, despite the State Department trying to stop you, it can’t be undone.
So, US citizens can become citizens of another country, and swear allegiance to them in the process, without losing their US citizenship. Unless you really intend to forfeit your US citizenship, doing those expatriating acts doesn’t appear to be very risky to your US citizenship.