That's a really good question.
-- Or was Natural Born Citizenship conferred on the basis of existing statutes? --
No, US citizenship was and is conferred by operation of the US constitution.
Article IV, section 2. The Citizens of each State shall be entitled to all Privileges and Immunities of Citizens in the several States.
Affected by the 14th amendment. 1. All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.
Congress has plenary power to define naturalized.
The Constitution is a statute. It is the highest law of the land. The Constitution did not define the term Natural Born Citizen, but clearly the framers did not intend that the children of slaves born in the United States would be considered as any kind of citizen at all.
Under "Natural Law" (referencing rights inherent by virtue of the creator) slaves would be considered Natural Born Citizens as they are endowed by their creator with whatever Natural Rights exist.
Citizenship has never been a Natural Right, it has always been conferred by the State under statutes or decrees.
Congress has the power and the authority to define whether or not Ted Cruz is a Natural Born Citizen and whether that is any different from a person who is born a citizen.
Congress will be given the opportunity when the electoral college declares Ted Cruz to be the elected president and congress is given the opportunity to certify the election.
Anyone want to take a bet that they would undo the presidential election based on this obscure phrase in the Constitution - the same Constitution that granted no rights - Natural or otherwise - to millions of slaves living in the United States at the time of it's passage?
It has a very simple two letter answer.