On the one hand, the survey depicts an American religious scene bursting with vitality. We are an overwhelmingly religious and largely Christian people: Only 4 percent of Americans describe themselves as atheists or agnostics, and nearly 80 percent identify themselves as Christian. The percentage of religiously unaffiliated Americans is on the rise -- one-sixth of the respondents fit that description -- but most reject the atheist and agnostic labels, and more than a third say that religion is somewhat or very important in their lives.

Yet our religious ties don't bind as they once did. More than a quarter of Americans have left the faith in which they were raised. That number jumps to 44 percent when movements among Protestant denominations are included.

This fluidity has touched every segment of American religion, and the results for almost every group are mixed. Protestants still account for a majority of the population, but that majority has slipped to a bare 51 percent. Non-denominational Protestant churches are gaining members, but Baptists and Methodists are losing them. Catholics remain America's largest single religious group with stable population levels, but gains among converts and immigrants have been offset by losses among cradle Catholics. Many of today's Buddhists and Jehovah's Witness adherents are converts, but those groups struggle to retain members. American Jews easily outnumber Muslims, but the disparate immigration and birth rates of the two groups suggest a reversal down the road.

"This is an incredibly dynamic religious marketplace," said Pew Forum director Luis Lugo. "Everybody has to scurry to retain their members and to gain new members."

That scurry has energized our religious scene and allowed America to resist the religious apathy and secularization that have engulfed other developed nations. Having to compete for members tends to make our religious leaders more responsive to their flocks and more ready to explain the contemporary relevance of ancient beliefs.

Yet living in a religious buyer's market has its drawbacks. Many religious leaders feel pressured to focus on style over substance and gimmicks over doctrine. Many seekers feel overwhelmed by options and discouraged that after years of adopting and discarding religious beliefs, intimacy with God still eludes them.

The Pew poll is a reminder to America's market-savvy religious leaders that their zeal for numbers should not stop them from telling the truth about authentic conversion. It is an ongoing process that demands perseverance, and its best fruit is borne in communities marked by commitment.

-- Colleen Carroll Campbell is an author, television host and St. Louis-based fellow at the Ethics and Public Policy Center. Her website is www.colleen-campbell.com.