Unfortunately, this matter has not been clarified at all by the framers. They never DEFINED the term in any of their writings and explications of the constitution. That’s the reason why we’re in this situation we are in. They didn't think to define it because it's meaning was very clear at the time... and I will explain why and how.
People keep citing Vattel ( see one of the posts above ). But we don’t even know if the framers were thinking of Vattel when they wrote this phrase. Why not Blackstone?
I'm glad you asked that question. I have searched the complete works of Blackstone, and if I recall properly, he uses the word "Citizen" exactly three times. In all cases he uses it to mean the inhabitants of a City. (As in the Citizens of London.)
Something a lot of modern people do not understand is that the word "citizen" did not mean the same thing in 1770s English that it does now. In old English, the word "Citizen" literally meant "someone who lives in a City."
Shakespeare uses the word a few times. He too uses it in context of the "Inhabitants of a City." The King James Bible uses it a few times, but it too refers to the inhabitants of a City.
I have checked Four English Law dictionaries from prior to 1770, and the word does not even exist in any of those English Law Dictionaries. It just isn't there.
Usage of the word "Citizen" to describe the members of a Nation was not a correct or normal usage of the word in 1770 English. The correct word for inhabitants of a Nation was "Subjects."
So if the word "Citizen" meaning "members of a nation", did not come from the English language, from whence did it come? As it turns out, the only place in the world in which the word "Citizen" meant members of a nation was in the Republic of Switzerland. (The only Republic in the World at that time.)
The Word "Citizen" had meant members of a country to the Swiss since their "Charte des prêtres" of 1370. (Considered to be the founding document of the old Swiss Republic.)
This makes a lot of sense because the Swiss Republic was cobbled together out of several independent states, and they were no longer "Subjects" of any Monarchy.
So why did the US Start Using it? Why didn't we use the word "Subject" just as we had always done before? Why did Jefferson deliberately eschewed this word to describe the Inhabitants of the New Independent States? Why did he deliberately chose to use this word "Citizen" in a manner that was not at the time, correct for the English language?
Well it's probably because they got the idea for creating a Confederated Republic from this book that was then currently sweeping across the nation. This book was called "Droit des Gens" (Law of Nations) and it was written by this Swiss guy who used the word "Citizen" to describe the members of a Republic which he suggested be created from a confederacy of Independent States. (Like Switzerland.)
Here is what this guy Vattel wrote in 1758.
Finally, several sovereign and independent states may unite themselves together by a perpetual confederacy, without ceasing to be, each individually, a perfect state. They will together constitute a federal republic: their joint deliberations will not impair the sovereignty of each member, though they may, in certain respects, put some restraint on the exercise of it, in virtue of voluntary engagements. A person does not cease to be free and independent, when he is obliged to fulfil engagements which he has voluntarily contracted.
Vattel used the word "Citizen" a lot. The English legal writers of the time seldom used it at all, and even when they did use it, they meant "Denizens of a City" or "City-zens."
So why did they not feel the need to define it? Because pretty much everybody at the time knew they got the word from Vattel, and he got it from the normal Swiss usage.
Blackstone, like his great predecessors Edward Coke and Matthew Hale, articulated the common law in various volumes. Their reliance on Magna Carta is eventually reflected in how the Founders wrote the Declaration of Independence and the Constitution, with its Bill of Rights.
The chain, in reverse chronological development, is that the Constitution was influenced by the common law, which was influenced by natural law.
The Constitution was an improvement over the common law, putting into one document designed to tie down and legally bind the government certain notions guaranteeing the separation of powers, federalism, and other structural protections of liberty and security from threats our own government would forever pose – because that is the nature of government. Changes to this structure of government, as have occurred unconstitutionally through the courts, the legislature, and the executive branch, are threats to the liberty and security of the people, who are the ultimate sovereigns in our American republic.
The common law recognized that laws governing society were capable of evolving, so long as the changes were not inconsistent with natural law and constitutional principles. From natural law we have the concepts of the security and sanctity of life, liberty, and property. Those rights are not granted by government, but instead are to be protected by government since they are inherent as given by God (“nature’s God,” hence, natural rights and the basis of natural law).
Common law developed through not just acts of the legislature and decisions of the judiciary, but custom (under certain conditions). The great English jurists who articulated important concepts of natural and common law also recognized that acts of the legislature or the King could be “unconstitutional” if inconsistent with the protections of the liberty and security of the people.
The American Constitution improved on that concept, making certain that even our elected officials were bound down by the Constitution through enumerated powers. Thus, we have a rule of law over government more perfect than Magna Carta and the common law.
An originalist view of the Constitution recognizes that of course laws governing society may evolve, but that the political class is not free to amend the Constitution without going through the amendment process, and certainly must not violate the Constitution, which is our fundamental and paramount law governing government. Alas, it is frequently violated by America’s biggest lawbreaker.
Those who rely on Blackstone for the interpretation of “natural born” as being born on American soil or only to the father when on foreign soil, should know that Blackstone was not construing a dictate of natural law, but was expressing an EVOLUTION of the concept of natural born.
Blackstone also recognized that children of the sovereign born on foreign soil were natural born. In America, the sovereign is not the King. With sovereigns inter-marrying with other sovereigns for political purposes, the allegiances of the time had somewhat different realities from today.
Note also that Blackstone’s interpretation of the law at the time would allow for “anchor babies.” He writes, “The children of aliens, born here in England, are, generally speaking, natural-born subjects, and entitled to all the privileges of such.”
The American law of sovereignty and inheritance is obviously different from an 18th Century English interpretation. Blackstone’s was not a natural law interpretation, nor a hard-and-fast rule for defining “natural born” that should govern an originalist interpretation. Indeed, the American law of naturalization and citizenship was intended to be left to legislative construct. The Civil War constitutional amendments applied to former slaves, and were an overdue correct application of a natural law flaw in American law, but consistent with the Declaration of Independence.
A number of law professors, who probably are not originalists but whose views I believe to be sincere, have indicated that one may not be consistent in claiming to be originalist and insist that Ted Cruz is a natural born American citizen.
So, it can be argued that because Ted Cruz’s mother is an American, it makes him natural born and eligible to be president.
And of course, His personal allegiance to America is unquestionable.