Obama's purported birth certificate indicates a foreign father, precluding his eligibility for not being a "natural born citizen" (NBC) born in U.S. of U.S. citizen parents (plural) as deduced directly from and required by Article 2, Section 1, of the Constitution. See the essay "Obama is Not An Eligible Natural Born Citizen" at www.ObamaBirthCertificate.net for the detailed logical proof.
POTUS must be a NBC, not just a citizen. The meaning of a NBC is not ambiguous by being undefined in the Constitution. The Constitution doesn't define any terms. The words: defined, definition or meaning, aren't in the Constitution.
The usurper Obama's birth certificate and other identity anomalies, pertain more to if he's even a U.S. citizen!