--and Barry Goldwater was born in Arizona before it was a state.
The big problem here is that in 1936 the Canal Zone was considered sovereign US territory. The democrats made a big stink in the 70's to convince everyone that it was not a US territory. Now, the government of Panama considers anyone like McCain to be a Panamanian.
If elected, McCain would be the first president with dual citizenship.
Who cares? He would still be a natural-born US citizen.
Actually, the treaty did not grant sovereignty to the US, as indicated by the preamble and Article III.
http://www.yale.edu/lawweb/avalon/diplomacy/panama/pan001.htm