I'm with you.
If in doubt, revert to natural law. In this case, I see no difficulty.
Isn’t Cruz a Cubanadian?
Your namesake would not so easily trade principles for perceived temporary electoral advantages.
According to the ENGLISH Version of Natural law, Because Ted Cruz is born in Canada, he owes his allegiance to Canada. According to the VATTEL version of Natural law, Because Ted Cruz's father was Cuban at the time of his birth, he owes his allegiance to Cuba.
So where would "natural law" support the argument that he is a "natural born" American? The Naturalization law under which he acquires citizenship was an artifact of 1934, not 1787. It was a gift from Congress, not a manifestation of "natural law."