The Northern Virginia doctor knows at least that much about his situation. He knows he is no longer considered a citizen of the United States — the place where he was born, went to school and has practiced medicine for more than 30 years — and that he also belongs to no other place.

A letter from a State Department official informed him that he should not have been granted citizenship at the time of his birth because his father was a diplomat with the Embassy of Iran. The letter directed Sobhani to a website where he could apply for lawful permanent residence.