Under what part of U.S. law was Marco Rubio supposedly naturalized at birth?
Minor v Happersett
“Additions might always be made to the citizenship of the United States in two ways: first, by birth, and second, by naturalization. This is apparent from the Constitution itself, for it provides that
“No person except a natural-born citizen or a citizen of the United States at the time of the adoption of the Constitution shall be eligible to the office of President, and that Congress shall have power “to establish a uniform rule of naturalization.” Thus, new citizens may be born or they may be created by naturalization.”
Clear - either new citizens are born or they may be created by naturalization. Naturalization doesn't cover those born as citizens. Those who are born as citizens are natural born citizens.
Natural law is not one man's view in one book. U.S. law should always reflect our best understanding of natural law - OUR best understanding - not the best understanding of an 18th Century Swiss philosopher.
That is your problem. You simply refuse to understand the blindingly obvious: using a law to confer any form of citizenship is an act of naturalizing a person who woould not but for the act of law otherwise be a citizen. By contrast, a person is a natural born citizen requires no statutory law or act of government to be a citizen. This is the difference between being a subject made or citizen made versus a subject born or a citizen born. A person who was a subject made at birth is not a natural born citizen simply because they were naturalized at birth by the intercession of a man-made law.
I've said it before, and I'll say it again. No doubt you'll simply disregard it yet again.
Vattel was neither the first nor the last to write a treatise discussing the definition of a natural born citizen. European governments had been applying the concept of a natural born citizen for centuries prior to the drafting and adoption of the U.S. Constitution. The Romans insisted upon the Citizen of Rome being born and educated only by Roman Citizen parents:
Quare, si fieri, potest et verba omnia et vox huius alumnum urbis oleant, ut oratio Romana plane videatur, non civitate donata. (Quintilianus, Institutio Oratoria, Book 1, Chapter VIII)