At Opinio Juris, Peter Spiro comments:
[The natural born Citizen clause] is a terrific case study for demonstrating constitutional evolutions outside the courts. No court will ever touch the question at the same time that particular cases show us where the law is.
One recent addition to the mix: [Neal] Katyal and Paul Clement have this piece on the Harvard Law Review Forum arguing that Ted Cruz qualifies as “natural born”. If Katyal and Clement say he is natural born, then he is natural born, merits aside. Bipartisan pronouncements from legal policy elites become a source of the law.
But in my view the Katyal and Clement essay says more about originalism than it does about evolving constitutionalism.
Katyal and Clement are not originalists; they are advocates (former Acting Solicitor General under President Obama and former Solicitor General under Bush 43). Yet their argument is almost entirely originalist. They begin by saying:
While some constitutional issues are truly difficult, with framing-era sources either nonexistent or contradictory, here, the relevant materials clearly indicate that a “natural born Citizen” means a citizen from birth with no need to go through naturalization proceedings.
They then rely on:
(1) British statutes from the eighteenth century (adding "The Framers, of course, would have been intimately familiar with these statutes and the way they used terms like “natural born,” since the statutes were binding law in the colonies before the Revolutionary War. They were also well documented in Blackstone’s Commentaries, a text widely circulated and read by the Framers and routinely invoked in interpreting the Constitution.");
(2) Immediate post-ratification practice in the 1790 Naturalization Act (adding "The actions and understandings of the First Congress are particularly persuasive because so many of the Framers of the Constitution were also members of the First Congress.").
(3) The Framers' purpose, based on the likely intent of John Jay, who apparently first suggested the clause; and ...
... that's it, except for a passing reference to the Senate's unanimous resolution that John McCain was eligible despite birth in the Panama Canal zone.
In sum, Katyal and Clement make an almost purely originalist argument. To be sure, it's not novel to do so -- many people have made originalist arguments about the clause (including me). What's noteworthy, though, is that Katyal and Clement are acting not as constitutional theorists or originalist bloggers but as advocates trying to persuade the greatest number of people of Senator Cruz's eligibility. As Professor Spiro says, they are speaking as members of the "legal policy elite," putting a stamp of constitutional approval on the candidacy. And in that capacity, their judgment is that originalist arguments are persuasive and sufficient.
Now this does not necessarily show that originalism is our law (as Will Baude has argued), but it does strongly suggest that originalism is at least a part of our law -- enough that leading members of the "legal policy elite" think it makes their case on this subject.