My friend David Burke, veteran youth pastor and church consultant, met recently with leaders of a midsized congregation to help assess their youth ministry. When lunchtime rolled around, a lanky 20-something pizza delivery guy wandered into the church’s youth room with several pizzas. When he realized where he was, he stopped short. He stood in the doorway for a moment, taking it all in: the poster-covered walls, the slouchy couches, the piano in the corner.

“You’ve been here before, haven’t you?” David ventured.

The pizza guy paused, thinking back. “Yeah. I think the last time I was here was the day I got confirmed.”

Souls in Transition, the impressive second installment of findings—and the first longitudinal sounding—from the massive National Study of Youth and Religion, is about the pizza guy and his 18- to 23–year-old age-mates, the most religiously disengaged cohort in the U.S. Principal investigator Christian Smith, assisted by Patricia Snell, returned to young people originally interviewed in 2003 to see how their religious lives had changed.

Smith, a professor of sociology and director of the Center for the Study of Religion and Society at the University of Notre Dame, is a gutsy sociologist who does not mind tipping sacred cows or poking around in areas that theologians like to claim for themselves such as religious formation. His earlier book (with Melinda Lundquist Denton), Soul Searching: The Religious and Spiritual Lives of American Teenagers, reported the first wave of NSYR findings. In 2007 Mark Oestreicher, then president of Youth Specialties, called Soul Searching one of the ten most influential youth ministry books—a first for a secular book on the sociology of religion.

In 2004, Smith and his team demonstrated that religion matters to American teenagers and that it contributes mightily to adolescent well-being. But they also discovered that what most American teenagers call faith is what Smith dubbed moralistic therapeutic deism, an interpersonal riff on American civil religion that tends to masquerade as Christianity but bears few similarities to the historic teachings of the Christian church and is mostly used to lubricate relationships. The remarkable consistency between the religious outlooks of teenagers and parents led Smith to conclude that moralistic therapeutic deism has colonized Ameri can churches and is now the dominant religion in the United States. Soul Searching ends with an odd admonition: a team of sociologists urges congregations to get down to business and teach their faith traditions to teenagers.

Souls in Transition is a denser and in some ways more sobering volume that represents a field-shaping contribution to the growing literature on emerging adults (young people roughly between the ages of 18 and 30). As developmental tasks once associated with the teen years reach into the twenties and thirties, ministry with emerging adults shows signs of becoming the new youth ministry of 21st-century congregations. Compared to people in other age groups, emerging adults are less likely to attend religious services weekly, pray daily or affiliate strongly with a religious tradition (a fact consistent with their tendency to resist institutional affiliations generally). Yet on some measures (thinking about the afterlife, taking the Bible literally, self-identifying as liberals) they reflect the adult population as a whole.

The big story in Souls in Transition is continuity: highly devoted emerging adults almost always start out as highly devoted teenagers, and religiously disinterested youth are unlikely to become interested as they grow older. (Most teenagers in the NSYR who committed to God did so before age 14.) When religious change occurs in emerging adulthood, it tends to be in the negative direction. What makes the faith of some young people more durable than that of others seems to be the presence of formative religious influences in their lives while they are teenagers (especially religious parents, but also other faithful adults), teenagers’ personal embrace of faith, a lack of religious doubts, multiple religious experiences, and personal faith practices, especially prayer and Bible reading.

Some of Smith’s findings run counter to popular wisdom: “Frequent teenage prayer is more influential than having a lot of religious friends, and both are more important than going on missions or service trips.” Smith remarked in a Christianity Today interview that some people “are going to be disappointed that going on mission trips doesn’t appear to amount to a hill of beans” in young people’s faith formation. People who work with adolescents will immediately recognize that some differences between teenage and emerging adult faith can be chalked up to developmental readiness as well as sociological variables.

Smith’s acknowledgment of a role for religious experience is unusual for a sociologist. He finds that having many religious experiences as a teenager—defined in the NSYR as committing one’s life to God, having a definite answer to prayer, experiencing a miracle or having a moving spiritual experience—is strongly associated with religious devotion through emerging adulthood, sometimes compensating for the absence of religious parents or congregational ties.

Smith saves his most intriguing analysis for a discussion of the implicit cultural influences of mainline Protestantism and American evangelicalism (for example, a Muslim girl describes her “personal relationship with God”). Drawing on sociologist N. Jay Demerath’s thesis that “liberal Protestantism’s core values—individualism, pluralism, emancipation, tolerance, free critical inquiry, and the authority of personal experience—have come to so permeate the broader American culture” that these values no longer need liberal Protestantism to survive, Smith makes a fascinating move: he argues that young people are not more involved in American religious life because they don’t have to be. The values of America’s dominant religious outlook for the past century are now carried forward by American culture itself. Smith contends that many emerging adults have bought into an implicit “mainline-liberal Protestant” perspective on American culture and “would be quite comfortable with the kind of liberal faith described by the Yale theologian H. Richard Niebuhr in 1937 as being about ‘a God without wrath [who] brought men without sin into a kingdom without judgment through the ministrations of a Christ without a cross.’”

Far from being in decline, Demerath suggests, liberal Protestantism has won in American culture. Yet many mainline Protestants do not see themselves in the limp version of Protestant liberalism that Demerath describes: a collection of modern values that omits the theological story providing the interpretive key for appropriating these values in Christian communities. Some mainline Protestants have given up on placing liberal values in conversation with the historic texts and traditions of the Christian community, but many have not. Recent interpreters of liberal theology (a diverse bunch: postliberals like George Lindbeck and Stanley Hauerwas, “revised” postliberals like Kathryn Tanner and David Ford, and progressives like Diana Butler Bass, Serene Jones, Jim Wallis and James Logan) insist on telling the gospel story for the sake of critiquing the church’s soul-less slide into something like moralistic therapeutic deism. The gospel gives liberal values redemptive traction, acknowledging the limits of human optimism by offering real hope in God’s activity through human communities.

Souls in Transition hints strongly that churches must provide frameworks that anchor and shape young people’s growing up, helping them reach beyond “subjective desires and feelings, on which alone it is not possible to build good lives.” This means starting when children are young—certainly before they turn 14—and continuing our relationship with them through their early adult years. While most American institutions drop out of young people’s lives during emerging adulthood, churches are uniquely equipped to practice the art of spiritual accompaniment, sharing a way of life with young people that participates in God’s activity in the world before, during and long after confirmation, until young adults are ready to spiritually accompany someone else. Smith’s research offers us hope, but not a blueprint. Churches should take it from here.