And what reason do you have not to believe it?
And neither does the Supreme Court, the rest of the legal system, any conservative legal organizations, or any major conservative politician.
That is irrelevant as to whether or not it is true. Do not base your understanding of the truth on what the crowd says. That is a fallacy called "Argumentum ad Populum." (Argument that the crowd agrees with you.)
To know what is the truth regarding the original and correct meaning of the term "natural born citizen" you have to do research as to where the term originated and what was it's intended purpose.
I have pointed out to people many times, if your interpretation of the term does not prevent foreign influence, how can it be correct if it doesn't accomplish what the founders intended?
A Definition that does not accomplish the task intended for the term, is an incorrect definition.
I reject the Vattel argument for many reasons, the big one being that until 2008 no one ever seriously argued that Vattel was used to define American citizenship. I have studied US history for years - lets just say that Vattel is not a name that pops up very often. Show me some serious legal articles in the past 50 years that talk about Vattel and NBC and then we will talk.