What possible advantage would it give him to claim any citizenship other than American?
Since Obama's records at Occidental College have been sealed, we don't know anything for certain.
BUT. We do know that he had an Indonesian roommate, and apparently lived in the foreign student dorm.
And we do know that free scholarships were being offered at the time for foreign students. So, why wouldn't Stanley Ann and Barry jump at the chance of free college? Even if supposing that he was considered an American citizen by American law, which is another question, he evidently had Indonesian citizenship. All he had to do was say that he was Barry Soetero, Indonesian, and he would get to go to Occidental College for free. For that matter, he would be admitted there when possibly he wouldn't qualify under ordinary circumstances.
How do you know this? I've seen birthers claim it all the time, but I have yet to see any evidence of this claim. Got any?