Dual citizenship is fine for everyone EXCEPT those who want to be President. Natural born citizenship prohibits such split allegiences.
You mean IF the person in question initiated the citizenship. Obviously Iran could have issued citizenship to George W. Bush while he was President. That would not have disqualified him.
And we have never 100% clearly determined if anyone can be of a non-American parent and be President. After all, our current President was KNOWN by everyone to have had a foreign father and no one ever said a thing, loudly or otherwise. NO ONE in the mainstream media, even on our side, said that he wasn't a natural born citizen because his father was foreign. Wouldn't Bobby Jindal also not be natural born? I think that could be a good definition, but it has not yet been clearly established.