A natural born Citizen is a “Citizen” according to “natural law” as explained by the author of the 14th Amendment Citizenship Clause below…

“This amendment which I have offered is simply declaratory of what I regard as the law of the land already, that every person born within the limits of the United States, and subject to the jurisdiction thereof, is by virtue of natural law and national law a citizen of the United States.” (Congressional Globe, Senate, 39th Congress, 1st Session, pg 2890)

Therefore, Barack Obama was not a Natural Born Citizen, and was ineligible for the Presidency. And, even if they are born here, anchor babies are NOT Natural Born Citizens, because their parents are not citizens.