Billed as "the largest gathering of the secular movement in world history," the Reason Rally -- a march on Washington by atheists and other non-believers on Saturday, March 24 -- is a coming-out party for a movement that has gained momentum in recent years.

It is also a glimpse at a major demographic category that will help decide this year's presidential election.

Whereas religious conservatives are correctly seen as the backbone of the modern Republican Party, often overlooked is the fact that the non-religious population has become the most reliable base for Democrats.

Religiously unaffiliated voters supported Barack Obama over John McCain 75 percent to 23 percent in 2008, according to the Pew Research Center, a stronger level of support than any major religious category.

Similarly, looking at church attendance, those who "never" attend religious services -- a group comprising 16 percent of the electorate -- were the strongest Obama supporters, giving him a 67-to-30 margin over McCain.

Thus, while surely there are some conservative atheists (just as there are some liberal evangelicals), the common perception of the culture wars pitting "secular progressives" against the "religious right" has some validity.

The Reason Rally aims to demonstrate that the seculars are finally finding cohesion, a sense of solidarity that has been previously lacking.

Indeed, although the religious right has been visibly flexing its muscle since the Moral Majority helped elect Ronald Reagan in 1980, seculars have remained a largely ignored voting bloc.

Open religiosity has become a basic prerequisite for most GOP candidates, but strangely the situation is not much different for Democrats. Except in the most liberal districts, even Democratic candidates now frequently go out of their way to emphasize religion.

Such Democratic claims of piety have not gone unnoticed by the secular demographic, which often sees elections as a choice between bad and worse, between one candidate who is dismissive of their views and another who is openly hostile.

When religion is indisputably exalted, secularity is necessarily marginalized. One nation under God, indeed.

This political embrace of religion, however, has hardly proven to be a formula for success for liberals. As the role of religion in politics has expanded for over three decades, the realities of American life have been sobering: labor in shambles, a disappearing middle class, and corporate profits and CEO pay at record levels while ordinary citizens confront insecurity and declining real pay.

With the one exception of the relatively successful gay rights movement, modern liberalism has been in constant retreat mode, an unequivocal failure.

The collapse of American liberalism would have been unimaginable before the rise of the religious right, but today a vision of truly progressive public policy is what seems illusory.

The economy was sent plummeting into chaos in 2008 due to unregulated financial markets, yet deregulation nevertheless remains the persistent mantra of one entire party and much of the electorate.

To the typical secular progressive, this is almost surreal.

As candidates now hold prayer rallies, routinely deny evolution, and talk seriously of restricting access to not just abortion, but even birth control, seculars have started to realize the importance of finding their voice.

This is reflected in unprecedented secular activism -- atheist political lobbying, widespread ad campaigns, and rapid growth of secular student groups on college campuses and even high schools -- and is now culminating with the Reason Rally.

As the secular emergence continues, one must wonder what it will mean for the American dialogue.

For over three decades, political debates in America have often centered on the issue of appeasing religious conservatives. On reproductive rights, stem cell research, public expressions of faith, and a host of other issues, the question was always: What will religious conservatives think of that proposal?

With the Reason Rally, the secular demographic is standing up to demand that a new question be asked: What will seculars think of that proposal?

Clearly, given the low state of affairs in America -- where a leading public commentator refers to his opponents as sluts -- little harm could come from making room at the table for a segment of the population that centers its world view on critical thinking and reason.

The secular demographic does not claim to have a monopoly on rationality, but it does feel that it has something to offer. By rallying in Washington, seculars are not whining about some imagined victimization, but rather they are exercising a voice that has been silenced for too long. On March 24, hear them roar.

David Niose is president of the American Humanist Association and author of the forthcoming book, "Nonbeliever Nation: The Rise of Secular Americans."