I will post a more complete response in a few hours, but for now let me just say that you are off base. The class of citizens who are natural born citizens is not now and never has been as limited as you speculate. You are simply wrong and ill-informed.
John, your posts are very good and helpful. I have enjoyed reading them. We have the same perspective.
Maelstrom, you have identified criteria you believe identifies a “natural born citizen,” but it has no binding legal authority. Historically, there have been several different ways a person could become a citizen without operation of a statute. They could be born on the soil, born under the authority, born to one citizen parent, born to two citizen parents, etc.
Every one of those is “natural.” It is a principle of long standing that a mother or a father may pass on what they hold title to in their own name. It simply isn’t necessary or just to deny the born person what is theirs by birth. Now if the situation is “complicated,” as you put it, because a person possesses two sets of citizenship rights, that does not cancel out the natural means by which they acquired those natural rights.
However, they do have the power to renounce one in favor of the other, and so remove the complication. This also is a natural and not a statutory right. The founders considered it essential to the American idea of citizenship that a person should have the right to expatriate, to disown one citizenship in favor of another, and furthermore this was for them under the domain of natural law, an expression of a fundamental human freedom.
So Cruz, having disowned his Canadian citizenship, has a clear and unclouded title to his naturally acquired American citizenship. There really is no problem here, other than the apparently desperate effort by some to read into the Constitutional text details it does not contain.
Peace,
SR