This is what made Mc Cain "eligible"
S.Res. 511 (110th): A resolution recognizing that John Sidney McCain, III, is a natural born ...
Obama, Pelosi and a few others signed of on this.
That resolution was based on the Tribe/Olson opinion. And it really didn’t make McCain “eligible” to run. The Senate Resolution has no force of law. The matter was never brought to the courts. The definition of “natural born citizen” as it applies to eligibility to serve as President and Vice President has never been resolved.