Um...duh? I'm sorry; I missed the whole memo where we were only supposed to vote for those with some sort of Christian religion. It is interesting that 39% of the population would have voted in an atheist; says something when there's supposedly a religious litmus test...
I think that an atheist would have had a chance, until the various fundie atheists started attacking the religious. When you attack someone's faith and do so in a way just to show your own moral and intellectual superiority, then you generally nuke your own chances of being taken seriously.
You also need to show that you are better than the system that you are displacing. Although there a number of secular charities, there are almost no specifically atheist charities (the only one I think of are the various Luther Burbank ones); if you are so better than religion, then you need to provide the same support network as the various churches.
Worse, there is a certain level of academic dishonesty. It's interesting that atheists have no problem pointing out that Christianity starts war simply because the leaders were Christian, but the same argument can't be applied to atheist leaders such as Stalin or Mao. For that matter, it's not even willing to admit that it's a form of religion, despite meeting the criteria of same.
In short, if Atheism wants to be taken seriously, it needs to stop attacking religion, create a support network, and recognize that it is a religion. If it EVER does that, then people may actually be interested in voting one of its adherents in...
RG