Perhaps you could offer some third world dictator a bribe for him to declare Obama a citizen of his country thus making Obama a dual citizen and not qualified to be president.
Obama, having been born in Kenya, the son of a British citizen, and never having been naturalized in the US, is not a US citizen, and cannot legally hold any elective office.
It's not dual citizenship that is at issue, it's dual citizenship *at birth* that is a problem. Not even that really, since it would not matter if the country of a non US citizen or citizens, considered their child a citizen of that country or not. What matters is that there is/are one or two, Non US citizen parents.
So no need for the bribe. Obama had a non US citizen parent. Therefore, even if he is native born, in the modern meaning of the term, he's not natural born.