This Christmas Eve, among the beautiful poinsettias, familiar carols, and nativity scenes across America, there will be millions more worshippers than last Sunday—or any Sunday—filling churches to capacity for the first time since Easter. Whether out of tradition, guilt, a desire to please a loved one, or a sense of awakened piety, people who have attended church only once or twice (or maybe not at all) this year will gather to mark one of Christianity’s highest holy days.

Christmas-and-Easter Christians vary in how religious they consider themselves to be. Similarly, the congregations and denominations to which they nominally belong are often unsure what to make of them.

While self-reported religious belief remains high among Americans, affiliation and participation have declined. In most communities, and particularly in urban areas, it is no longer socially expected that everyone have at least some connection to a church. Americans still over-report their religiosity on surveys, but unaffiliated people today feel little shame in their estrangement from organized religion.

Religious leaders often use their churches’ nominal adherents in contradictory ways, depending on what fits their need or argument.

When numerical clout purportedly matters, religious institutions are happy to cite the largest number possible. For instance, when denominational lobbyists meet with Members of Congress, they do so on behalf of “15 million Southern Baptists” or “eight million United Methodists,” knowing that only a fraction of those attend church regularly.

The National Council of Churches touts its “37 member communions, including 45 million persons in more than 100,000 local congregations.” Similarly, the National Association of Evangelicals “represents more than 45,000 local churches from 40 different denominations and serves a constituency of millions.”

Yet every church bureaucrat acknowledges that membership statistics are inflated and, in any case, do not correlate to individual spiritual vitality, congregational health, or denominational effectiveness.

Churches may even spin numerical decline as a good thing. Shedding nominals, leaders say, helps the church distinguish true believers from the insufficiently devout. Since church culture is no longer dominant, elites are keen to emphasize the counter-cultural nature of religious life and commitment—an emphasis that regards millions of nominal adherents as harmful to the image of the church as subversive or even freakish.

The Reverend Dr. Ed Stetzer, president of Lifeway Research, says that the 75 percent of Americans who self-identify as Christian are divided into three roughly equal groups. “Cultural Christians” are Christians by heritage only. They do not practice a vibrant faith. “Congregational Christians” have some connection to a church and may even occasionally attend, but like Cultural Christians, they are not very faithful. Only the “Convictional Christians” truly count as worshippers, for they orient their lives around faith in Jesus Christ. “The Church is not dying,” Stetzer contends. “It is just being more clearly defined.”

My many friendships with liberal and conservative clergy confirm the notion that American Christianity has begun to embrace its smaller-yet-more-committed identity as an improvement over its postwar prominence, which leaders recall as culturally dominant if often lukewarm.

In fairness to this view, I concede Stetzer’s point that people are not necessarily practicing Christians simply because their culture tells them they are. I sympathize with pastors who have seen their congregations shrink for two generations while lapsed Christians declined repeated invitations to come back to church. The gospels make it clear that Jesus did not seek nominal followers.

Still, I’d like to defend nominal Christians—a group that, by Stetzer’s counting, may include as many as 150 million Americans.

It is offensive—laughable even—to assume that frequency of church attendance is our best measure of people’s knowledge and love of God. Everyone has delightful, even "Christlike" friends who never attend church. Likewise, we all know nasty, insufferable people who attend every Sunday.

If you talk to lapsed Christians, you find that comparatively few of them rejected God. They do not feel that the church rejected them (people who are gay being the notable exception here). Most often, people reject the church for a variety of reasons.

Sociologist Elizabeth Drescher has interviewed hundreds of religiously unaffiliated Americans. She generalizes the trend in this way: Lapsed Catholics feel hurt by the Church. Former evangelicals are often angry at their tradition. People leave mainline Protestant denominations largely out of been-there-done-that boredom.

In each case, churches not only fail to offer a compelling vision of lifelong Christian spiritual community, but they also often do not acknowledge their own fault in driving people away. The issues are different in each case, of course, but common problems include overbearing use of guilt and shame, anti-intellectualism, and not effectively countering the conception of religion as a commodity that eventually people may not want or need any longer.

On some level at least, Christmas-and-Easter Christians continue to make the Old, Old Story a part of their own stories. Far from being hostile to faith, they often have reservoirs of goodwill and gratitude for religion. Christianity meant something to them and their families and they feel compelled to pay homage to that heritage.

While there is no reason to believe that the de-churched will become devout, practicing Christians en masse, it remains true that they have significant resources for whatever Christian communities ultimately emerge alongside or in place of the institutional church. Lapsed Christians of various stripes often value ritual and tradition, have a deep knowledge of and appreciation for the Bible, and have a heightened social conscience.

As for the old dogma of extra Ecclesiam nulla salus (“outside the Church there is no salvation”), mainline clergy seem to have dropped it altogether even as evangelical leaders proclaim it more vociferously than any pope ever did.

Pastors and denominational elites are thinking carefully about their relationships with and responsibilities to their lapsed members. But blaming Christians who find themselves outside the care of a congregation is unfair. It is arrogant and hypocritical to count nominal churchgoers when numbers count but to suggest every other day that the particular denomination is better off without them.

With Jesus’ birth in Bethlehem, “the Word became flesh and lived among us, and we have seen his glory, the glory as of a father’s only son, full of grace and truth” (John 1:14). Rather than judging their lapsed brethren, observant Christians may want to think about how, on Christmas Eve of all days, he might be born in their hearts again.