Traditional religion in the United States has suffered huge losses in recent decades. The number of Americans identifying as "not religious" has increased remarkably. Religious affiliation, service attendance, and belief in God have declined. More and more people claim to be "spiritual but not religious." Religious organizations have been reeling from revelations of sexual and financial scandals and cover-ups. Public trust in "organized religion" has declined significantly. Crucially, these religious losses are concentrated among younger generations. This means that, barring unlikely religious revivals among youth, the losses will continue and accelerate in time, as less-religious younger Americans replace older more-religious ones and increasingly fewer American children are raised by religious parents.

All this is clear. But what is less clear is exactly why this is happening. We know a lot more about the fact that traditional American religion has declined than we do about why this is so.

Christian Smith is the William R. Kenan, Jr. Professor of Sociology and Founding Director of the Center for the Study of Religion and Society at the University of Notre Dame. Smith is well known for his research focused on religion, adolescents and emerging adults, and social theory. He has written many books, including Divided by Faith, Soul Searching, and Moral, Believing Animals. His new book is Why Religion Went Obsolete: The Demise of Traditional Faith in America.