Is John McCain a Natural-Born citizen?

The answer is, no one knows for sure. McCain was born to American parents in the US-controlled Panama Canal Zone. That makes him a US citizen, but does it make him a natural born one? From the New York Times:
Mr. McCain’s likely nomination as the Republican candidate for president and the happenstance of his birth in the Panama Canal Zone in 1936 are reviving a musty debate that has surfaced periodically since the founders first set quill to parchment and declared that only a "natural-born citizen" can hold the nation’s highest office.
Almost since those words were written in 1787 with scant explanation, their precise meaning has been the stuff of confusion, law school review articles, whisper campaigns and civics class debates over whether only those delivered on American soil can be truly natural born. To date, no American to take the presidential oath has had an official birthplace outside the 50 states.
"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."
I fear the worse. Imagine the entire election campaign being about a forthcoming Supreme Court ruling on the issue.
(Seen in picture is a fragment of a historical map of the Panama Canal Zone.)