WASHINGTON -- Is "Christian America" dying? And if so, should we mourn or cheer?

These questions, raised in a recent cover story written by Newsweek editor Jon Meacham, opened a vigorous and continuing debate (note: I am an occasional contributor at Newsweek). The article has been peppered with criticism from religious conservatives who say it demonstrates the anti-religious bias of the mainstream media. This reaction actually demonstrates something different: that it is easier to read a headline than it is to read an article.

The Newsweek cover declaring "The Decline and Fall of Christian America" was provocative in a typical, newsmagazineish sort of way. The serious essay that followed stated that the proportion of Americans who describe themselves as Christians (76 percent) has declined since 1990 -- which is true. That the percentage of Americans reporting no religious affiliation (15 percent) has increased -- which is undeniable. That the religious right has become less influential and less triumphalistic over the last several years -- and that this is positive for religion in general, which can become diluted and discredited by identifying too closely with any ideology, social order or nation.

The religious right, at least in its cruder expressions, is indeed a phenomenon without a future. A younger generation of evangelicals and their leaders, while generally remaining culturally conservative, tend to view the religious right's model of social engagement as too narrow in focus and too negative in tone. And the loose language of creating or re-creating a "Christian America" has always been a heresy, a historical error and a blunder. A heresy because no human kingdom, however admirable, can be properly identified with the Kingdom of God. A historical error because the federal government has been wisely nonsectarian from its beginning -- its laws informed by religious values while establishing no single, official religious tradition. A blunder because the conflation of faith and ideology can politicize, nationalize and thus diminish the appeal of faith itself.

So Meacham's arguments are accurate, even wise -- but they also are incomplete. John Green, a polling expert at the Pew Forum on Religion and Public Life, qualifies the Newsweek findings in several ways:

First, the rise of the religiously nonaffiliated is a trend -- but a very gradual one. According to Green, there is "no real difference between 2000 and 2009" on this measure.

Second, he notes that the unaffiliated are not identical to the nonreligious. In addition to a hard core of genuine secularists (who often seem positively theological in their proselytizing zeal), the unaffiliated include deeply religious people who distrust organized religion, along with people who are young or recently relocated and haven't gotten around to adopting a religious preference.

Third, Green observes that this group is "bigger, but not static." While some have consciously left their religious traditions, others raised without a religious tradition will eventually adopt one. Faith in America is fluid.

Fourth, Green argues, "the growth in the unaffiliated has not come at the expense of evangelicals, who continue to grow. It has come at the expense of mainline Protestants and white Catholics." The decline of the Protestant mainline is not a development I choose to cheer, because it has often represented the best of liberal idealism, particularly during the civil rights era. But one reason for the decline of the mainline is the very malady Meacham diagnoses on the right. The mainline has become pale, anemic and shrunken as it has become a reflection of trendy liberalism -- miniaturizing the Kingdom of God to fit a political ideology.

Fifth, Green warns that the polling could reflect not changing numbers of the unaffiliated, but changing pressures in society. "There used to be a strong stigma against being religiously unaffiliated. That has declined." When the pollster calls, it may simply be that "people are being more honest."

Green concludes that Newsweek has "told half of the story." "There are certain people moving to the left on cultural grounds. ... But we can't ignore the other side, the growth of more conservative believers -- evangelicals and conservative Catholics. ... We may not be seeing the decline of Christian America, but polarization on religious grounds."

This polarization is reason to mourn. But Green warns that we should be careful in allocating blame. "One reason could be the growth of a secular reaction against the Christian right. But it could be the other way around -- the reaction of the Christian right against the growth of secularism. Or they could feed off each other."