Re: Atheism
Who's to say we haven't had several atheist presidents? (or, for that matter, who's to say we haven't had bi- or homosexual presidents?)
What a politician professes publicly about his or her faith or lack thereof (or sexual orientation, or prejudicial views or what-have-you) and what a politician *actually* believes about faith (or their own sexual orientation, or whom they prejudge) are not necessarily the same. It shouldn't be surprising that a politician might compartmentalize his or her personal life, thoughts and beliefs from their public persona.
Compartmentalization seems to be a hallmark of our cultural ethos. It allows a person to be an obsessed 'American Idol' fan and still claim unwavering loyalty to a deity that decries allegiance to anything secular. Challenging such a person about the authenticity of their beliefs in the face of their actions typically results in an agitated emotional outburst and an illogical and defensive tirade. As a culture, we seem to cherish our myths and are perfectly happy to put walls around them and guard them from rigorous study and challenge... lest we be exposed to our own hypocrisy. All of this is perfectly normal behavior -- for a child or early adolescent.
To respond to the spirit of your question, "will we ever have a president who publicly expresses non-belief in deity or deities," I suspect that may one day happen. However, for us to get there our society and culture will have to mature and evolve significantly. To my mind, our culture has barely entered adolescence and in many ways is still quite childish. I wouldn't expect a cultural shift of that magnitude to occur during my lifetime.
