Casual observers of mainline decline often think that the trouble began in the ’60s, but [sociologist] Rodney Stark argues that the decline started much earlier. It’s only because of population growth in the mid-twentieth century that most of the mainline denominations started losing numbers in absolute terms decades after the problems began.

It’s easy to miss that Stark is talking about two related but distinct developments in mainline denominations. The first is a loss of basic faith among leadership and seminary/divinity school professors. He puts this point bluntly:

“I blame it all on the liberal seminaries . . . The fact of the matter is, if you look at the leading lights in American Protestantism in the early 20th century, the famous people didn’t believe in the divinity of Jesus. They were very shaky about the existence of God. They always talked about God, but when you got down into their books and pushed, God was some kind of social value. There wasn’t a one of them who believed in a God who could hear prayers.

Well, they may be right about God. But that doesn’t make for a strong church. As a matter of fact, it doesn’t make for much of anything.”

Stark also talks about the politically leftward drift of mainline leaders and bureaucrats:

“If you look at the National Council of Churches, and the Federal Council before it, and look at their annual statements and resolutions, they are exceedingly Left-wing. . . .

I’m not saying they’re wrong. I’m just saying that they are relentlessly Left, even on what might be considered traditional Christian positions. They are extremely, actively pro-abortion. They are constantly passing resolutions in favor of Cuba, and you couldn’t possibly get them to condemn the Soviet Union for anything.”

So Stark’s point is not merely that some Episcopal seminary professors started voting for Franklin Roosevelt, and so parishioners started going to the Assembly of God Church down the street. His point, rather, is that large swaths of the leadership in mainline denominations quit believing in, well, God, the incarnation, the resurrection, and other things Christians believed, and then they filled the void with left-wing politics. As a result of that one-two punch, the mainline denominations have been hemorrhaging members while evangelical churches and individual congregations have grown dramatically.