THE QUESTION:

Whatever happened to U.S. “Mainline” Protestantism over the past half-century?

THE RELIGION GUY’S ANSWER:

What’s known as “Mainline” Protestantism was pretty much America’s culture-defining faith till well after World War II.

Fifty years ago, these church groups still maintained high morale and together boasted at least 28 million members. But by the latest available statistics they’ve shrunk 45%, to 15.5 million. During those same decades, the U.S. population increased 61%.

Across U.S. religious history, nothing like this has been seen before. What happened?

We’re talking about several small denominations included with several larger bodies in the familar “seven sisters” — American Baptist Churches USA, Christian Church (Disciples of Christ), Episcopal Church, Evangelical Lutheran Church in America, Presbyterian Church (USA), United Church of Christ and the largest, the United Methodist Church.

The Religion Guy recently culled his basement library and came across two remarkably prescient books from a half-century ago, “The Gathering Storm in the Churches” (1969) by sociologist Jeffrey K. Hadden at Case Western Reserve University (and later the University of Virginia), and “Why Conservative Churches Are Growing” (1972) by the Rev. Dean M. Kelley, director for civil and religious liberty at the National Council of Churches (NCC).

Mainline groups share several key traits: predominantly white memberships, origin in Colonial times through the early 19th Century, ecumenical affiliations with the NCC and World Council of Churches, and pluralism that tolerates liberal religious thinking in contrast with the strictly conservative white “evangelical” Protestants. (Black Protestants often share evangelical traits but embrace a distinct subculture.)

Hadden’s book reported on his pioneering survey of 7,441 pastors in five Mainline Protestant groups (plus the conservative Lutheran Church-Missouri Synod), and incorporated survey data on lay Protestants in California as reported in 1968 by Rodney Stark and Charles Glock.

He said churches faced a dangerous and “widening gap” between lay members and clergy who were pursuing civil-rights activism (Vietnam War protests emerged later) and downplaying or shedding traditional religious beliefs. For example, only 49 percent of the Methodist clergy believed in “Jesus’ physical resurrection as an objective historical fact.”

Clergy revisionism on doctrine was strongly associated with devotion to liberal politics, but not so with lay members.