Because Obama’s father was Not a US citizen and his mother was under 21 when he was born, he is not a natural born US citizen. That is the law that was in effect at the time Obama was born.
If he was born in HI it’s a mute point, he is a US citizen regardless of his parents status. Illegal aliens do it every day.
If he was born outside the US, them mom must have been physically present in the US for 10 years, at least 5 of which were after the age of 14. So if she departed the US before that age of 19 she is ineligible to transfer citizenship and Obama did not derive citizenship at birth.
True, only if he was born out of the country.