In case anyone was wondering, the young Prince is a dual US-UK citizen. He has UK citizenship from his UK father. By §301 of the Immigration and Nationality Act, US citizenship is transmitted to him automatically because he is the child, born in wedlock, between a US citizen (Lady Meghan) and a foreigner (Prince Harry). The Lady Meghan may or may not be a UK citizen at this time, but that does not matter. For purposes of transmission of citizenship, at the time of Master Archie’s birth, all that counts is that she is a native-born US citizenship who has lived most of her life in the USA.
Master Archie will have a US passport — issued by the US Embassy in London. He will not need a green card or a visa to enter the USA.
The rules for transmission of US citizenship if one of the parents is a non-American are very complex and are a function of the date of the child’s birth, the US immigration status of the parents, the marital status of the parents at the time of the child’s birth, and sometimes, the amount of time the US citizen parent has lived within the borders of the USA.
Multiple citizenship and international taxation obligations are complex issues, and although many people think it would be fun to have multiple passports, there are serious taxation, travel, and other issues. If you have questions about multiple citizenship, please contact an experienced immigration and nationality attorney. –jcf