Here is an overview of the hurdles atheists face in American society:

For starters, consider that there is not a single self-described atheist in Congress today. Not one. It wasn’t until 2007 that Rep. Pete Stark, a Democrat from Northern California, became the first member of Congress and the highest-ranking public official ever to admit to being an atheist. (And even he framed it in terms of religious affiliation, calling himself “a Unitarian who does not believe in a supreme being.”) Stark was elected twice after this, but when the 20-term congressman lost his seat last year, it was to a 31-year-old primary challenger who attacked him as irreligious, citing, among other things, Stark’s vote against our national motto: “In God We Trust.”

Indeed, the same year that Stark came out, the Secular Coalition of America was able to identify only five atheist public officials in the entire United States. After Stark and a Nebraska state senator, the third-highest ranking atheist was a school-board president from Berkeley, Calif.—this despite the fact that, according to a 2012 Pew report, 6 percent of Americans say they don’t believe in a higher power. That leaves at least 15 million Americans without any elected officials to represent their point of view. Basically, atheism is still as close as it gets to political poison in American electoral politics: A recent Gallup poll found (once again) that atheists are the least electable among several underrepresented groups. Sixty-eight percent of Americans would vote for a well-qualified gay or lesbian candidate, for example, but only 54 percent would vote for a well-qualified atheist. Seven state constitutions even still include provisions prohibiting atheists from holding office (though they are not enforced). One of those is liberal Maryland, which also has a clause that says, essentially, that non-believers can be disqualified from serving as jurors or witnesses…

The Cold War changed all that. Atheism began to seem almost treasonous amid tensions between the United States and the Soviet Union, because the Soviets were officially and emphatically against religion. Sen. Joseph McCarthy famously used the phrase “godless communists” to bash the political left and others he considered his enemies. In this context, President Dwight D. Eisenhower signed laws in the mid-1950s inserting “God” into our Pledge of Allegiance and putting it on all our money. (It had been on most coins earlier, but Eisenhower made “In God We Trust” our national motto, henceforth to appear on all bills.)…

In fact, the fastest-growing religious category in the United States is what are called the “nones”—people who say they have no religious affiliation. One-fifth of Americans are in this group today, according to Pew Research Center polling. Among adults under age 30, a full third count themselves as religiously unaffiliated. Some of them believe in a god or gods; some do not. They are not going to want to be pushed around by any sect one way or another, and as their numbers increase, they won’t have to allow it.

Surveys consistently show Americans are more opposed to atheists than other groups (such as voting for President) even as organized religiosity declines and atheists look to form megachurches. Read more of the Pew report on religious nones which suggests the numbers are growing even as some still have more traditional religious beliefs and practices.