America tends to be one of the few places in the western world where this is even a problem. I’m an atheist and can’t recall any time when I’ve not been taken seriously just because I’m an atheist.  That being said I do live in New Zealand and from what I’ve experienced there is a bit of a believe what you want kind of thing here.Atheist are on a regular basis taken seriously (a lot of scientists are secular by any standard) but some religions do try to alienate the "not believer" by its nature maybe in a self defense response.

Atheism will not be taken seriously at least for a while, and I find it a great tragedy that half of a country would not vote for an atheist based only on that they are an atheist.