“Duh Won has already admitted he does not meet the requirements because of dual citizenship.”
That is incorrect. Factually, The One has admitted his father was a foreign national only.
That this does not meet the definition of NBC is an opinion substantiated nowhere in the Constitution, and therefore not a fact until a court so determines it.
NBC is indeed a term not defined in the Constitution. Neither are: Militia, arms, people, welfare, commerce, defense, or State defined. For those we must look at the references which show the definitions of the day, ones to which the Founders had access, just as someone today might look in a Dictionary to find the definition of "is".
When one looks at the definition in Vattel's and regards that Obama was a British Subject due to his Father's citizenship status, even the claim of dual citizenship is not enough to pass muster as a Natural Born Citizen, without conflicting loyalties.
So why do they, the courts, seem so darned reluctant to do that, one way or the other?
But it is a fact, a historical one, but just not a legal one, yet.