While the US was founded by primary secularists, you will never hear any of the extremist Christians (this includes the moral majority and a fair amount of the American Evangelicals) admit that. These are the people who earnestly believe the bible is written literal history and often then misinterpet the meanings of the passages.
I was actually quite shocked to find that a lot of the members of the administration of the US open the bible for "guidance" instead of looking at the consequences and information they have been given. To use a book to help you make a decision instead of basing it on reality and facts, is frankly disturbing.
The seperation of Church and State was meant to save the Church from the political arena, and the people from the Church. It was meant to be a choice, hence Freedom of Religion, which can mean (contrary to popular belief) freedom from religion. I personally was hopeful that the US would move away from supremely conservative Christianity, however with the implimentation of "Abstinence Only", the increased focus on marriage being only between a man and woman (woman being the primary baby makers), and the ridiculous blocks on advancement in medicine due to so called ethical disapproval (I'm all for people who want to have abortions donating the fetus to science for stem cell research)...it looks like the US has devolved into an almost dark ages, rip van winkle mindset.
If you are pagan, athiest, believe a man and man or a woman and a woman can get married, are pro choice, or are what the Christians consider a sexual deviant you become an outcast in a sense. People have become afraid of what they don't understand instead of moving forward to become educated about it.
I hope the US can overcome this plateau of intellectualism before it turns into "Idiocracy".