[Lurking Libertarian]

As to the other point, I understand that Indonesia did not allow dual citizenship—i may be wrong, show me the refernce on this—in which case the citizenship of the father ( adoptive) is passed to the son.

Not under U.S. law-- if you were born a U.S. citizen, you can never lose your citizenship unless you personally renounce it, as an adult, before a U.S. consular officer overseas. (See the U.S. Supreme Court's decision in Afroyim v. Rusk). Your parents could renounce your citizenship 100 times when you were a child and it would have no effect.

[cycle of discernment]

Ok, thanks, one less wrinkle to factor in.

[SirJohnBarleycorn]

you can never lose your citizenship unless you personally renounce it, as an adult, before a U.S. consular officer overseas

Actually, the statutory provision in effect in the late 1970s and early 1980s provided additional ways to lose US citizenship as an adult besides personally renouncing it to the State department.

For example, if Obama took steps to secure his Indonesian citizenship as an adult, such as applying for and obtaining an Indonesian passport claiming Indonesian citizenship, that would likely have done the trick, without the US State Dept necessarily ever having been notified.

[mad_as_he$$]

I remember reading somewhere that if your parents renounced you citizenship you had to reclaim it within a certain time after turning 18. I will look and see if I can find that. I still have a question as to if that law ever existed and if it did when was it in force.