[Drew68]

Is that proof going to require documentary evidence that both parents were American citizens at the time of birth???

Probably not since:

A. Parents' citizenship at time of birth is irrelevant to the eligibility of an American-born candidate and...

B. How would a candidate go about proving the citizenship status of his parents? Would a candidate have to submit his parents' birth certificates as well? His parents' naturalization paperwork? What if the candidates parents are deceased? File a FOIA request with USCIS?

Anyways, it's a moot point. See A. above.

[Uncle Chip]

Parents' citizenship at time of birth is irrelevant to the eligibility of an American-born candidate

Not according to the definition of "natural born citizen" by Justice Marshall in the Venus decision of 1814, history of qualifications of American Presidents, and the Senate's own SR511.

[Lower55]

“A. Parents’ citizenship at time of birth is irrelevant to the eligibility of an American-born candidate”

True. Unless they are a candidate for President or Vice President. Then Parents have to be citizens for the child to be Natural born.

[LorenC]

"Is that proof going to require documentary evidence that both parents were American citizens at the time of birth???"

Probably not since:

A. Parents' citizenship at time of birth is irrelevant to the eligibility of an American-born candidate and...

As evidenced by the fact that Spiro Agnew served despite having a non-citizen father. And as further evidenced by how no one ever pressed John Kerry on the question of his parents' citizenship. Or Ralph Nader. Or Mike Gravel. Or Bill Richardson. Or Michael Dukakis. Or Geraldine Ferraro...

http://barackryphal.blogspot.com/2010/01/presidentialvp-candidates-with.html