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."