Natural born citizen has never been defined by the Supreme Court nor should it be because it is probably a political question not presenting a justiciable issue within the court’s power to decide. Political issues and questions are solely within the purview of Congress.
That doesn’t mean the concept of natural born citizen is in any way uncertain. A natural born citizen is anyone who is a United States citizen “at birth.” If one’s mother is a citizen, whether natural born or naturalized citizen, one is a natural born citizen even if born outside the United States. Congress could change that, but it has not. It could not do so without starting a firestorm of protest. Therefore, it won’t.
This means that even if Obama were born in Kenya he is a natural born citizen because his mother was a citizen. Ted Cruz became a citizen at his birth in Canada because his mother is a citizen. Same for John McCain, Barry Goldwater, Chester A. Arthur, Charles Evans Hughes, George Romney, Lowell Weicker, Marco Rubio, Bobby Jindal, Obama advisor Valerie Jarrett who was born in Iran, and likely millions other Americans born outside the U.S. to parents who are citizens.
Much ado about nothing, indeed.