You are correct that the term “citizen” for purposes of the 14th Amendment has been defined. What has never been defined is “natural born citizen” in the context of Article II.
What Leo is arguing is that “natural born citizen” means “citizen of the United States with no other citizenship status from another sovereign at the time of birth.” I’m not saying that he is correct, but your analysis that the term “natural born citizen” has been defined by the Supreme Court for the purposes of Article II is incorrect.
Yes it has, several times. By federal legislation and through Supreme Court decisions. Both have defined what qualifies as natural born citizen as someone born in the U.S. and subject to its laws.
What Leo is arguing is that “natural born citizen” means “citizen of the United States with no other citizenship status from another sovereign at the time of birth.”
And I cannot see anything in the Constitution that supports his interpretation.
...but your analysis that the term “natural born citizen” has been defined by the Supreme Court for the purposes of Article II is incorrect.
Since the Constitution is silent on what the definition of natural born citizen is, then the definition arrived at by Congress and the Supreme Court is the one and only definition. For the purposes of Article II and every other purpose.