Steme Miller’s understanding of this issue is way behind that of most of those who have been following it. In fact, the law he quotes only applies if Obama was born outside of the US, as has been stated many times here on FR. According to the 14th Amendment to the US Constitution, anyone born in the US is a natural born US citizen.
The only way for O’Bama to not be a citizen is if his mother was married to his father and he was born outside of the US. If the mom was single and O’Bama were born outside of the US, O’Bama would obtain the same status as his mother-regardless of her age or time as a citizen.