6 Thoughts on Ted Cruz and the US Constitution.

1. The Motivation: I spent some time reading up and researching this, especially after some prodding in an argument online, on the historical record of the law regarding 'natural born'. I had always suspected that Ted Cruz might be ineligible, because I'd long known about the distinction between being born overseas on a US base, and not, but I didn't know the history of the concept of naturalization. My journey started with this constitutional law professor's post.
2. Common Law, Statutes, and the US Constitution: The US Constitution and the laws we have, were mostly (as one would rightly expect) conveyed from British Common Law. According to Common Law, 'natural born' referred specifically to those who were born on British soil. There were exceptions, namely, the children of those British subjects sent overseas by the King, in service of the King. In 1351, King Edward III issued a Statute that expanded the rights of citizenship to those who were born overseas to parents, both of whom were British subjects. 
3. Expansion of 'Natural Born' Definition?: While it has been said that British Common Law and the Statutes enacted prior to the passage of the US Constitution were considered to be the basis of the US Constitution (per SCOTUS in Patterson v. Winn) it should be noted that the British Statute in question, only expanded the scope of citizenship, not the definition of natural born. However, for argument's sake, if Edw III's Statute was the basis for interpreting the US Constitution, I think it comes out worse for Ted Cruz, because his father was not a US Citizen at the time of his birth, which, if strictly holding to the original British Statute, would mean that Ted Cruz should not be allowed US Citizenship.
4. Citizenship: There are four routes to citizenship: (1) Being born in the US and its territories which is a reference to jus soli, or 'right of soil'; (2) and (3) Acquisition and Derivation, references to jus sanguinis, or 'right of blood', where you either acquire citizenship because you were born to American citizens, or derived citizenship because you were born to naturalized parents; (4) Naturalization, where you apply for, and pass a test. Just a reminder, that these represent expansions of the path to citizenship, beyond the original US Constitution, and strictly speaking, jus soli is the only means towards citizenship that hasn't changed since the 14th Amendment.
5. Anchor Babies: In tonight's GOP debate, Ted Cruz suggested that, if we were to disqualify him, then other people on the stage would also be disqualified (Donald Trump and Marco Rubio). It was a baffling argument, because he was referring to his pet peeve, 'anchor babies'. Now, as noted above, citizenship is one part of the qualification to become President, but the critical half that was left out by Cruz, was being a natural born citizen. Furthermore, the citizenship clause that allowed for 'anchor babies' is clearly written in the 14th Amendment, as opposed to a disagreement on what it means to be 'natural born'. It's not just self-serving to exclude the part of the US Constitution that doesn't fit your needs, but it's hypocritical for an Originalist.
6. An Originalist or Not?: Ted Cruz considers himself an Originalist, that is, he believes that laws should strictly interpreted to the US Constitution's original meaning. No matter how you slice it, Ted Cruz does not appear to meet the qualifications to become President. If you take the original intention of King Edward III's Statute as an expansion of natural born, you have to also take the rest of the Statute that required both parents to be citizens. The interesting part of this, is that the 1790 Naturalization Act states, "the children of citizens of the United States, born out of the limits and jurisdiction of the United States, shall be considered as citizens of the United States:   Provided, That the right of citizenship shall not descend to persons, whose fathers have never been resident of the United States." Passed around the time of the US Constitution, clearly the Framers never meant for someone like Ted Cruz, to qualify as a US Citizen! So if Ted Cruz is true to his Originalism, he can't run for President. So you see, Originalist or not, Ted Cruz is disqualified.