Who will determine whether John McCain is a "natural-born citizen," qualified for the presidency?

There's been a lot of discussion of whether John McCain meets the constitutional requirement for the presidency. He was born in the Panama Canal Zone, where his father was stationed as a military officer. The NYT covers the story today:

“There are powerful arguments that Senator McCain or anyone else in this position is constitutionally qualified, but there is certainly no precedent,” said Sarah H. Duggin, an associate professor of law at Catholic University who has studied the issue extensively. “It is not a slam-dunk situation.”...

Senator Lindsey Graham, Republican of South Carolina and one of Mr. McCain’s closest allies, said it would be incomprehensible to him if the son of a military member born in a military station could not run for president.

“He was posted there on orders from the United States government,” Mr. Graham said of Mr. McCain’s father. “If that becomes a problem, we need to tell every military family that your kid can’t be president if they take an overseas assignment.”

I love the contrast between the academic and the politician, and I think the politician's legal sensibility here says more about how the Supreme Court would ultimately decide the question than any academic inquiry into the text and the history of the constitutional clause. Graham, by the way, is a lawyer (with a law degree from the University of South Carolina) and more than 6 years of service as a lawyer in the Air Force. He still serves in the Air Force Reserves, where he is a colonel and a Senior Instructor at the Air Force JAG School. He knows law, and his interpretation of the clause is not just political instinct.

Ms. Duggin and others who have explored the arcane subject in depth say legal argument and basic fairness may indeed be on the side of Mr. McCain, a longtime member of Congress from Arizona. But multiple experts and scholarly reviews say the issue has never been definitively resolved by either Congress or the Supreme Court....

Lawyers who have examined the topic say there is not just confusion about the provision itself, but uncertainty about who would have the legal standing to challenge a candidate on such grounds, what form a challenge could take and whether it would have to wait until after the election or could be made at any time.

And this is the point: No one should be seen as having standing to sue. No one who might conceivably file a lawsuit has a concrete and particularized injury that would be redressed through the disqualification of McCain. So there will not be a Supreme Court case interpreting the clause. If the Electoral College ever selects someone who presents this problem, it will be theoretically possible for Congress to reject the choice on constitutional grounds, but, politically, that too is inconceivable.

The real constitutional interpretation is taking place right now, as we decide whether to accept a man with this problem as the nominee, and later, as the candidate. I think we as a people have already answered the question as to McCain. None of his opponents are using disqualification as an argument and no one is concerned about it. Think of how different it would be if Arnold Schwarzenegger ran for President. The issue would be debated and argued, and I think we'd see him as disqualified and, because of that, he'd never reach the point of nomination. Can you picture Barack Obama or Hillary Clinton trying to defeat McCain by making the argument that his birth in the Canal Zone disqualifies him? They'd only make themselves look bad. The argument is so unattractive that no one serious will make it, and therefore the question, for all realistic purposes, has already been answered.

ADDED: Jim Lindgren peruses the historical texts and concludes that the answer is obvious (and McCain is "natural-born").