[Old Teufel Hunden]

"If the father is not a US Citizen, then the child is not a “natural born citizen”

Where in the constitution does it say this?"

It doesn't. The people who claim this stuff go back to Vattel and his "Law of Nations" which admittedly was consulted upon and known to the founders when they came up with the requirements for the Presidency. The term "Natural Born" comes from Vattel. He said that a Natural Born person was someone who was born in their country to parents who are citizen(s) (plural not singular).

However, these same founders went on to further define in the Naturalization act of 1790 (notice that is the very first Congress) what a Natural Born Citizen is. We don't need to consult Vattel. The Founders defined it legislatively. In that act, it said any person (it was white person at the time, later laws included everyone) born in the United States is "Natural Born". There were other exceptions also such as born outside the U.S. to American citizens, but the first one is the only one we need to know in regards to shooting down this argument birthers make.

[wrench]

Age and Citizenship requirements - US Constitution, Article II, Section 1

You might like to do some more research.

[Mach9]

If what you say is true (1790 clarification), then why did Chester Arthur hide and lie about the fact that his father was not a U. S. citizen?

[ml/nj]

The term "Natural Born" comes from Vattel.

It was around for a long time before Vattel. He just used it. Here's what the OED says:

Pay close attention to the example from 1709.

ML/NJ

[philman_36]

In that act, it said any person...born in the United States is "Natural Born".
Perhaps you should read the law and get back with me.
“An act to establish an uniform Rule of Naturalization” (1790 & 1795).

I don't see what you see.
1790...And the children of citizens of the United States that may be born beyond Sea, or out of the limits of the United States, shall be considered as natural born Citizens: Provided...

1795...the children of citizens of the United States, born out of the limits and jurisdiction of the United States, shall be considered as citizens of the United States: Provided...

[wideminded]

However, these same founders went on to further define in the Naturalization act of 1790 (notice that is the very first Congress) what a Natural Born Citizen is. We don't need to consult Vattel. The Founders defined it legislatively. In that act, it said any person (it was white person at the time, later laws included everyone) born in the United States is "Natural Born".

Actually the Naturalization Act of 1790 says: "And the children of citizens of the United States, that may be born beyond sea, or out of the limits of the United States, shall be considered as natural born citizens. ... ".

I don't see anywhere else that this law mentions the term "natural born". So it doesn't exactly define "natural born citizen", although probably someone could make a case that the definition is implied. Nor does this act discuss the case in which one parent is not a citizen.