â€œWeâ€™re here! Weâ€™re godless! Get used to it!,â€ chanted the crowd of 20,000 or so atheists at this past weekendâ€™s Rally for Reason in Washington, D.C. As the chant suggests, the protesters styled their event on the National Mall (which was not affiliated with Reason magazine in any way) as a â€œcoming outâ€ party for atheists. One participant even carried a sign ripped off from the heyday of gay rights demonstrations: â€œHi Mom. Iâ€™m an Atheist!"

The rally was advertised as the largest ever gathering of atheists, agnostics, freethinkers, and other assorted faithless folks. The relatively young crowd was treated to talks, rants, and routines by such faithless luminaries as biologist Richard Dawkins, American Atheists president David Silverman, professional skeptics Michael Shermer and James Randi, mythbuster Adam Savage, profane musician Tim Minchin, and (via video) comedian Penn Jillette. Off to the side was a small collection of Christian counterprotesters (including members of the truly awful Westboro Baptist Church) who assured the assembled nonbelievers that Christianityâ€™s loving God would consign them all to everlasting fiery damnation unless they changed their wicked ways.

But it is not just Westboro Baptist kooks who dislike atheists. Polls show that most Americans are uneasy (to say the least) with unbelievers. Consider a Pew Research poll from June 2011 that found that 33 percent of respondents said that they would be less likely to vote for a candidate who was homosexual and 62 percent said that it would make no difference. For atheist candidates, the numbers were basically flipped: 61 percent of respondents said that a candidate's atheism would make them less likely to vote for them and only 33 percent said it would make no difference. A June 2011 Gallup Poll reported that only 49 percent of voters would vote for a â€œwell qualifiedâ€ presidential candidate who was an atheist. The next lowest vote percentage went to a gay candidate for whom 67 percent would consider voting. The good news for atheists is that the trends are moving in the right direction: in a 1958 poll only 18 percent said that they'd vote for an atheist.

In fact, a side-by-side comparison of polling data finds that tolerance for theological deviance is evolving slower than acceptable of what used to be called sexual deviance. In 1977 a Harris poll reported that 55 percent respondents thought that gays should not be allowed to be teachers but 80 percent said they could work in factories; now 69 percent say itâ€™s OK for them to be teachers and a later survey finds that 89 percent believe that gays should have equal rights in terms of job opportunities. Atheists as a group lag behind in acceptance when compared to gays; a recent study found that only 33 percent of respondents would hire an atheist as a day care worker, but 65 percent would hire them as a waitress.

Itâ€™s no wonder that atheists poll so badlyâ€"religious folks believe that the godless are about as trustworthy as rapists, at least according to a recent study. In â€œDo You Believe in Atheists? Distrust is central to anti-atheist prejudiceâ€ [PDF], published in Journal of Personality and Social Psychology in December. The researchers reported that religious participants in the study regarded atheists as being more criminally untrustworthy than rapists. "Outward displays of belief in God may be viewed as a proxy for trustworthiness, particularly by religious believers who think that people behave better if they feel that God is watching them," explained University of British Columbia psychologist Ara Norenzayan, one of the researchers on the study. "While atheists may see their disbelief as a private matter on a metaphysical issue, believers may consider atheists' absence of belief as a public threat to cooperation and honesty." In a 2003 study [PDF], 48 percent (the highest of disapproval rating of any group) of Americans said that they would disapprove of their children marrying an atheist.

This distrust prompts one to wonder if believers really do worry that people would engage in rampant murder and mayhem if they thought that there was no vengeful deity monitoring their behavior at all times. In fact, psychological research does confirm that a lot of religious believers do tend to think this way. In light of those fears, one prominent slogan featured on placards at the Rally for Reason, â€œBe Good for Goodnessâ€™ Sakeâ€ must appear nonsensical to believers.

Distrust of atheists has an long intellectual pedigree. After all, Athenian philosopher Socrates was convicted for, among other crimes, preaching atheism (which he artfully denied). Eighteenth century liberal British philosopher John Locke is thought to have jumpstarted the notion of the separation of church and state in his A Letter Concerning Toleration. However, even Locke believed that atheists were not to be tolerated. â€œPromises, covenants, and oaths, which are the bonds of human society, can have no hold upon an atheist,â€ he wrote. In addition, Locke asserted, â€œThose that by their atheism undermine and destroy all religion, can have no pretence of religion whereupon to challenge the privilege of a toleration.â€ Only believers have the standing to demand that their beliefs be tolerated by the state.

â€œGod and government are a dangerous mix,â€ warned Annie Laurie Gaylor, co-president of the Freedom from Religion Foundation at the rally. Believers especially would do well to keep this fact in mind. Lockeâ€™s proposal for the separation of church and state was an idea devised to prevent the legal domination of one sect over other dissenting sects. As Locke well appreciated, mixing government and God has proven to be a sure recipe for civil strife and often war. The government should be secular, reserving civil society as the non-coercive arena for religious practice and contention.

Unfortunately, some politicians, most especially including this seasonâ€™s flock of would-be Republican presidential candidates want to inject a little more God into government. Their loud professions of faith may, however, be provoking a backlash among voters. Another Pew poll reported earlier this month that the percentage of Americans who say that there is too much public expression of religious faith among politicians rose from 12 percent in 2001 to 38 percent now. Sadly, 30 percent still think there is too little faith-mongering by politicians and 25 percent believe the amount is just about right. Even better news: 54 percent now say that churches should keep out of politics, whereas only 40 percent think that they should express views on social and political questions. Back in 1996, 54 percent thought churches should meddle in politics and only 43 percent wanted them to butt out.

Voters will certainly bring their religious convictions (or lack thereof) into the voting booth with them. But what the constitutional principle of separation between God and government prevents is setting religious tribes against one another in a fight over political favors and the distribution of tax dollars.

In its March 12 issue, Time magazine listed â€œThe Rise of the Nonesâ€ as one of the biggest trends in the U.S. It turns out that fastest growing religious group in the United States are Americans who list their religious affiliation as â€œnone.â€ A Pew survey found that 16 percent of Americans are unaffiliated with any religious group; about of whom half could be described as secular unaffiliated. Twenty-five percent of Americans aged 18 to 29 are unaffiliated with any particular religion. If this trend toward nonbelief continues, itâ€™s going to be harder and harder for believers to â€œhateâ€ atheists because the damned nonbelievers are going to turn out to be people they already love and value, their children, other relatives, friends, neighbors, and co-workers.

See the Reason.tv video, "What We Saw at the Reason Rally," by my colleagues Joshua Swain and Lucy Steigerwald below:

Disclosure: I have been â€œoutâ€ as an atheist since by early teens, and as far as I know I have never suffered discrimination based on my lack of belief in an omniscient Sky God.

Ronald Bailey is Reason's science correspondent. His book Liberation Biology: The Scientific and Moral Case for the Biotech Revolution is now available from Prometheus Books