You need to read the law that was in force at the time. It has quite detailed stipulations regarding how to determine citizenship.
If you take the time to read the law, it appears that Stanley Durham's circumstances at the time would not confer citizenship to Obama, IF he was born outside the USA.
I posted the letter from Saloon because I was trying to show how stupid the Obama supporters are! They were never taught American History. To Them anyone can be president!