All the talk about Obama, Bennet, Cruz, Harris, etc not being eligible is all a waste of time. If the candidate was born in US or born overseas to at least one US citizen parent, the candidate is eligible. Why? Because the eligibility of a Presidential candidate has never been argued before SCOTUS. Therefore, no precedent. SCOTUS will therefore use any tenuous thread to rule in favor of candidate and avoid disrupting a political party.
Democrats may elect usurpers, but too many Republican voters still believe in the Constitution for the GOP to do it.
You may be able to nominate an ineligible GOP candidate, but you won’t elect one.