When first avowing his religious credentials for president, Barack Obama said – and then repeated many times since – that “secularists are wrong when they ask believers to leave their religion at the door before entering the public square.”

The party that will soon nominate Obama is to be praised for its acceptance of and respect for its religious members. However, it is the nonbelievers who are now being ignored.

Hearing of the plans for the prayer/unity/values event leading off the convention on August 24, Ron Millar, Associate Director of the Secular Coalition for America, wrote a letter on July 2 to Leah Daughtry, CEO of the Democratic National Committee and planner of the “big tent” event. He asked Daughtry if nontheistic Americans were welcome and, if so, how this would be manifested.

While not replying directly to the Coalition, Daughtry did discuss the request with the Associated Press.

“Atheists speaking at an interfaith service…does that work?” a “befuddled” Daughtry was quoted as asking in a July 19 story by the AP’s Eric Gorski. “I don’t quite know. But they’re part of the party, you treat them with respect.”

The first sign that treating them with respect was not a priority for Daughtry was her lumping all notheists who include not only agnostics but also humanists, skeptics, and believers in spirit but not a personal god into atheists.

And the second came with the announcement of the lineup for what had once been thought of as a “values” and a “unity” event: no one represents the millions of secularists. Daughtry: “Democrats have been, are and will continue to be people of faith – and this interfaith gathering is proof of that.”

But what about those Democrats who are not “people of faith?” Are they not invited? Or invited just to watch others pray? Should their own outlook not even be acknowledged?

If the Democrats are trying to strike unifying chords among their entire kaleidoscopic range of liberals, moderates, and progressives, it should be obvious that secularists cannot dare be left out of the “big tent” event, and that it should be about beliefs and values, not solely about religion.

Secularists remember all too painfully one of the most dramatic presidential addresses in American history. At the National Cathedral three days after September 11, 2001, the president’s speech so filled with religious language that it was virtually a sermon.

As he delivered it, Bush stood flanked by Jewish, Muslim, and Christian representatives, with no one invited to stand alongside them whose presence might acknowledge the existence of the tens of millions of secular Americans.

At this most important collective moment in the recent history of the United States, it was as if their president was telling them that they did not exist. The United States had become a nation of believers.

Yet one of the most remarkable implications of the data presented in the new Pew U.S. Religious Landscape Survey is that atheists, agnostics, secular humanists, and believers in an impersonal God or universal spirit — people who do not believe in God at all or who do not believe in a traditional God — will be a huge share, perhaps as much as 40 percent of Democratic voters in November.

Another Pew discovery: Two out of every three Americans say that their moral values do not come primarily from religion. In other words, whatever their faith, these are people who live largely or wholly secular lives.

It turns out that deciding to welcome faith into the public square was the easy part. Now the rest of the Democrats – the many with underlying beliefs that can’t be neatly categorized as “religious” – must be invited to join the political conversation as well.

Thomas Jefferson glimpsed such problems when he called for a “wall of separation” between church and state, treating the first as private and the second as public. In any case, excluding some so that others feel included is no way to create common ground.

Ronald Aronson is the author of “Living Without God” and a distinguished professor of the history of ideas, an interdisciplinary atudies program in the Department of History at Wayne State University in Detroit, Michigan.