In case you missed it, the president of the United States called the nation to prayer on May 5 — just as past presidents have done on the first Thursday of every May since 1952.

Mandated by Congress, the National Day of Prayer is marked this year by events around the country, many of which are organized by the National Day of Prayer Task Force, an evangelical Christian group that maintains the self-described “official site” on the web for celebrating the day.

A government-sponsored “prayer day” is an anachronism, a vestige of a bygone era in America when the majority faith was often imposed as a national creed. For much of our history, minority faiths, as well as atheists and secular humanists, have been mostly invisible and seldom heard in the public square.

But in 2011, we live in a very different country. Millions of Americans pray openly and freely to a bewildering variety of gods and goddesses — and a growing number to none-of-the-above. One “prayer day” no longer fits all, if indeed it ever did.

Despite expanding religious diversity, most Americans (76 percent, according to a 2010 First Amendment Center survey) still support a Congressionally mandated day of prayer. Nevertheless, the practice hasn’t gone unchallenged.

Last year, a federal judge in Wisconsin struck down the statute authorizing the National Day of Prayer as a violation of the establishment clause of the First Amendment. But last month, the 7th U.S. Circuit Court of Appeals overturned the decision, ruling that the group that brought the case, the Freedom From Religion Foundation, did not have standing to file suit (a feeling of alienation, the court determined, is not sufficient harm).

On other fronts, atheists, freethinkers, and secular humanists, often lumped together in the news media as “non-believers,” are beginning to have some success in leveling the playing field for the growing number of Americans who have no religious affiliation (around 16 percent in most polls).

Just last week, to cite the most recent example, three atheists in Tulsa, Okla., including the local leader of the Freedom From Religion Foundation, were given licenses to perform marriages by the county clerk’s office. What has long been limited to religious organizations is now open to secular groups — at least in Tulsa.

Meanwhile, on a national level, atheist and secular humanist groups are pushing hard for a military chaplain. Although “atheist chaplain” may strike some as an oxymoron, atheist groups say that all service members should have access to counseling and other forms of support from someone who shares their beliefs. Some 9,400 military personnel identify themselves as atheists or secular humanists, and there are probably many more among the 285,000 service members who claim no religious preference.

Atheists, freethinkers and secular humanists don’t pray, but they have beliefs, values, and community. By demanding licenses to perform marriages, and atheist military chaplains, these groups now seek equal treatment.

This effort makes Constitutional sense. Under the First Amendment the government is required to be neutral — not only among religions, but also between religion and non-religion.

If the state bestows legal recognition on religious groups, then the state must also give the same privileges and benefits to non-religious groups.

As for prayer, it’s time to take the “national” out of the National Day of Prayer and let Americans organize a multitude of prayer days — or no prayer day — according to dictates of conscience, not proclamations of governments.

Charles C. Haynes is director of the Religious Freedom Education Project at the Newseum.