Cathedral of Our Lady of the Angels, in Los Angeles. Photograph: David Butow/Corbis Saba

In Spring 2008, the Pew Forum on Religion and Public Life published the results of its U.S. Religious Landscape Survey, a national sampling of the religious affiliations of more than 35,000 Americans undertaken over the summer of 2007. The news drawn from it, at least as widely summarized in the media, amounted to three main headlines. One: For the first time in American history, Protestantism is close to becoming the faith of fewer than half of all Americans (51.3 percent). Two: There is a substantial minority of religiously unaffiliated Americans (16.1 percent). And three: The Catholic Church would be much diminished in its current share of the U.S. population (23.9 percent) if it were not for Hispanic immigrants.

What are we to make of these findings? We have known since the 1960s that mainline Protestantism (loosely composed of Episcopalians, Presbyterians, and Congre-gationalists) has been on the decline—at least in terms of membership (not, necessarily, in political and cultural influence). Although we have witnessed the surging importance of evangelicals in American politics since about the 1980s, their growth has not been sufficient to compensate for the mainline losses and thus to preserve for much longer the numerical dominance of Protestants in America.

The increase in the religiously unaffiliated is among the few big changes in American religion since the 1940s, when pollsters first began documenting Americans’ religious preferences and church-going habits. In 2002, the sociologists Michael Hout and Claude Fischer (writing in American Sociological Review) documented a dramatic twofold increase in unaffiliated Americans during the 1990s, from what had been a fairly stable 7 percent from the 1970s through 1991, to 14 percent in 1998. The data they used came from the reputable General Social Survey run by the University of Chicago, which has gathered data on religion almost annually since 1972. Pew’s results show that this shift continues.

It bears noting that the increase in the unaffiliated does not reflect an increase in American atheism. (Only 1.6 percent of respondents in the Pew study identify themselves as atheist.) Many unaffiliated individuals—more than one-third of them—say that religion is important in their lives. And, although Pew did not ask this specifically, we know from other studies that many religiously unaffiliated people are active spiritual seekers. Even in the absence of a denominational attachment, it seems clear, belief in the sacred matters.

For the Catholic Church, the Pew study indicates patterns of loss and patterns of gain. Whereas almost one-third (31 percent) of Americans were raised Catholic, only a quarter of American adults (or close to 24 percent) self-identify as Catholic today, a net loss of 7 percent. By contrast, the Baptists, the largest Protestant denomination, have lost only 4 percent of their childhood adherents. Nonetheless, as is well-documented by a number of studies, the proportion of Americans who are Catholics has remained relatively stable over the past several decades, the gap filled to a large degree, as Pew affirms, by Hispanic immigrants.

Not all Hispanics are Catholic, to be sure; some 23 percent are Protestant, predominantly evangelical. But the “market-share” dependence of the U.S. Catholic Church on Hispanic immigrants makes a good headline, and probably gives some satisfaction to critics of the Catholic hierarchy who cannot fathom otherwise why long-term statistical trends would show an overall pattern of stability in Catholic affiliation despite the various controversies and scandals in which the Church has gotten embroiled. The larger point to be made, however, is that patterns of religious affiliation and church attendance are always related to broad social, political, and demographic forces. The Catholic Church in the United States would not have achieved much numerical strength in the first instance had it not been for the immigration trends of the 19th century. Church composition—and Church doctrines and practices—do not remain static, and we should not be too surprised by change. Change happens.

The Pew report uses the language of “winners and losers” in describing the changing composition of the American religious landscape. Its authors are not the first to do so—the theme is well-established among academic researchers. But numerical gains and losses do not speak to commitment within a church, nor do they necessarily reflect how a church’s presence is felt in society at large. Sometimes, as Benedict XVI has intimated, less can be more: A church whose vast lay membership is characterized by doctrinal diversity (another survey reports that 32 percent of America’s Catholics attend weekly Mass, for instance, while 34 percent say they never attend), may have to sacrifice numbers as it tries to transmit a coherent religious identity to later generations.

Or maybe, just maybe, doctrinal diversity is the way to grow. Only time will tell.

If one had to name the social institution most closely entwined with Church participation and the religious socialization of the next generation, it would be marriage. (Married adults with school-age children have a higher Church commitment than many other demo-graphic groups.) In April 2007, the U.S. Conference of Catholic Bishops, through its 20-year-old Committee on Marriage and Family Life, enlisted Georgetown University’s Center for Applied Research in the Apostolate (CARA) to survey U.S. Catholics on issues surrounding the sacrament of marriage. As researchers Mark Gray, Paul Perl, and Tricia Bruce relate in their summary, the bishops were particularly interested in learning the extent to which Catholics understand the Church’s teaching on marriage; the laity’s attitudes in general toward marriage; and Catholics’ personal experiences of marriage. CARA issued Marriage in the Catholic Church: A Survey of U.S. Catholics (1,008 adult Cath-olics, to be exact) in October 2007. Clearly, the bishops’ attention was not driven solely by long-term considerations of religious socialization, but by more immediately urgent pastoral concerns: As the CARA researchers report, 23 percent of adult Catholics have gone through a divorce, with 11 percent now divorced and remarried (figures comparable to the U.S. population as a whole). Further, only 15 percent of divorced Catholics have sought an annulment; of those, almost half (49 percent) were granted one.

Two-thirds of currently married Catholics were married in the Church. An additional 5 percent tied the knot in civil marriages that were subsequently blessed—that is, convalidated—by the Church. In other words, a substantial proportion of currently married Catholics are in marriages that the Church does not recognize.

This is a very complicated Catholic reality. Each of these issues alone—broken marriage, divorce, annulment, remarriage, marriage outside the faith—presents pastoral, doctrinal, theological, and canonical challenges. Together they reflect a (relatively) silent crisis in the Church. Many divorced Catholics, not surprisingly, are estranged from the Church, choosing, for themselves and their children, to go without the Church’s rituals and guidance. The Church in turn loses out on the stock of everyday experiences that these individuals and their families can contribute to the fabric of Catholic parish life. Fewer divorced Catholics than married Catholics attend weekly Mass, but the attendance rates for both groups are low—12 percent and 26 percent, respectively. Given the prevalence in society at large of divorce and of its triggers (financial strain and work/family time pressures, included), and the relatively low weekly church participation of Catholics, the extent to which Church tenets can buffer Catholics against divorce is questionable. Nor is the increased presence of Hispanic Catholics in the United States apt to do much to stem Catholic conformity to the broader American trends in marriage and divorce: Hispanic Catholics are less likely than whites to report that their parents are married to each other. They are also more likely than whites to have divorced parents—27 percent compared with 13 percent.

The realities of Catholic marriage are not easily reducible to a language of winners and losers. They pose challenges to the status of the sacraments in Catholic theology and in Catholic lives that transcend any simple ledger. Religion in the United States has been remarkably adaptive thus far. From the early Puritans, who approved theologically diluted “halfway covenants” for the less religiously committed second generation, to the increased flexibility shown by Catholic tribunals in nullifying American Catholics’ marriages since the 1970s, religious institutions accommodate their practices to changing cultural norms. These shifts, of course, create new dilemmas, but they can also maintain a certain religious vibrancy. Challenges do not invariably spell decline, but represent renewed opportunities for visionary leadership. An immediate challenge confronting all churches in the United States is whether they can secure the attention, if not the loyalty, of young Americans: Among 18-to-29-year-olds, as Pew documents, one in four report no religious attachment.

Michele Dillon is a professor of sociology at the University of New Hampshire and the author of In the Course of a Lifetime: Tracing Religious Belief, Practice, and Change (with Paul Wink, 2007).