Like many other Americans over the centuries his father was stationed "abroad" (albeit in the Canal Zone which was treated as American territory by the law) with his wife and children.
The law, at the time, would have specified that any children born to his mother and father while abroad should be added to the "family visa" or "other documents" dealing with the fact of their assignment outside the US.
End of story.
What happened was the Democrats were quite upset that their own spawn, the Leftwingtards at DU, were attacking McCain on this basis when, in fact, they knew their possible candidate, Obama, had an even worse problem.
McCain is a useful idiot for the Democrats like Specter.
Maverick John McCain stabs conservative Republicans in the back regularly and pushes amnesty with his buddies Lindsay Graham and Mel Martinez.
McCain is a despicable human being. Not as bad as Obama but we were stuck with Obama thanks to McCain. His campaign manager was a Democrat who pretty much gave up in Sept 2008. They also attacked Palin along with the McCain clan. McCain is another Arlen Specter.