I am not sure this is true, despite the law.
Berg makes reference to the Hague Convention of 1930. Although treaties are not supposed to override the Constitution, I am not sure what the situation is with respect to statutory law. I suspect the treaty comes first as long as it is not in violation of the Constitution.
Berg argues that by the Hague convention the US, as a party, has agreed to respect other countries laws regarding citizenship. In particular, if another country prohibits dual citizenship and you become a citizen thereof, then you necessarily become a non-citizen of the US.
I don't understand where he gets this from the Hague convention, but maybe I am missing something.
This is the official USG policy on dual nationality.
Berg argues that by the Hague convention the US, as a party, has agreed to respect other countries laws regarding citizenship. In particular, if another country prohibits dual citizenship and you become a citizen thereof, then you necessarily become a non-citizen of the US.
This just simply isn't so. We have millions of Americans who hold dual nationality in this country, including holding passports from those countries, e.g., Israel, Ireland, etc.
"A U.S. citizen may acquire foreign citizenship by marriage, or a person naturalized as a U.S. citizen may not lose the citizenship of the country of birth.U.S. 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 U.S. citizenship. In order to lose U.S. citizenship, the law requires that the person must apply for the foreign citizenship voluntarily, by free choice, and with the intention to give up U.S. citizenship."