美国承认双国籍？
Dual Citizenship/Nationality
Contrary to general belief, the United States does recognize dual nationality (the simultaneous possession of citizenship in more than one country.) [b]The Supreme Court of the United States has stated that dual nationality is "a status long recognized by the law", and "that a person may have rights and be subject to the responsibilities of more than one country.[/b] Asserting the rights of one citizenship does not by itself mean renouncing the rights of another citizenship. In general, the country in which a dual national resides has a predominant claim upon them.
http://www.unh.edu/oiss/immigration/perm_res.html 最下面。