The issue is confounded by the actual details of his birth. Firstly, Frank Davis is more than likely Barrack's real father, who at the time was a CIA agent. So in reality he would have been a US citizen even if he was not born in the US, because both of his real parents were US citizens. Them needing to doctor his birth certificate would also make sense if they needed to change who his father really was or was born elsewhere.

There is some evidence to suggest that BO mother was a CIA asset. There is some possibility that BO and FD chose Obama as the "father" had something to do with some CIA plan at the time, or simply done to prevent FD from getting in trouble impregnating his asset.

Additionally personally I have seen enough circumstantial evidence to suggest that BO was raised to be a CIA asset as well (think MKULTRA/Project Monarch style), which is why he was helped into college by Talal despite poor grades before and during his tenure, was into "community organizing" (helps CIA infiltrate these groups to direct and control them), and why so few people remember him when at college (CIA often recruits people non MKed before college to have them spy on dissidents and professors at college).

As someone who checks ID's and what not for a living, there were several markers on the birth certificate that showed manipulation, as the government trains it people to look out for. I said that since it was released, though at the time I still felt he was US citizen (the paper in Hawaii mentions his birth) and they did it to fuck with people, which is strange because the CIA certainly had the capability manufacture one with no defects, so I'm sure they released it under the presumption it would convince every day folk and allow them to marginalize people who claimed it wasn't authentic.