McCain is a Panamanian citizen, born in Colon in Panama outside the former Zone. Although he may well also be a U S Citizen, he is not a "natural born" citizen under Article II, Sec. 1, Par. 4 of the Constitution and is thus not eligible to hold the office of President of the United States.
The Sense of the Senate Resolution to the contrary is all very interesting but it is the kind of direction to the Supreme Court from Congress that the Court usually ignores.
McCain is not a Panamanian citizen. Very few countries, the US being one of them, grant citizenship solely based on being born in the country.
And McCain is a natural born citizen- he was a citizen at birth due to his parents both being American citizens. His place of birth is wholly irrelevant. There is simply no rational argument that can be made that the child of two American citizens is not a citizen from birth, and therefore not a natural-born citizen.
Senator McCain did not require being "Naturalized", therefore he is a natural born U.S. citizen.
My daughter was born on Portuguese Air Base No. 4 (Lajes Field) but obtained a Certificate of Live Birth Abroad from the U.S. State Department. At no point was she a foreigner. The only thing we told to do when we returned to the ConUS was register her birth with the State of Georgia.