My answer has changed in the past seven years. Now, it's whether the candidate (a) is free of obvious mental illness, (b) possesses a fundamental degree of adult temperament and behavior, (c) has a basic working knowledge of global politics, (d) possesses an above average intelligence and standard human curiosity, and (e) can be depended upon to be civil, articulate and decent, and not constantly engage in behaviors for which we would scold our children.
Then the normal standards for a President would apply. But not before then.
Prior to 2016, I never had to even think about that first part.