Liberal beliefs pulling Mainlines further down

By Mark Tooley*

March 2019 – There’s a pervasive narrative today of conservative Christian demographic decline. This narrative is partly based on reality and partly based on wishful thinking by some. But this narrative typically ignores the far more dramatic implosion of liberal white mainline Protestantism.

The popular conventional narrative asserts that young people in droves are quitting evangelical Christianity because it’s too socially and politically conservative. Of course, the implication is that if only Evangelicalism would liberalize, especially on sexuality, then it might become more appealing.

But all the available evidence as to what happens to liberalizing churches strongly indicates the opposite. Mainline Protestantism is in many ways what critics of Evangelicalism wish it would become. And yet the Mainline, comprised primarily of the “seven sister” historic denominations (See chart.), has been in continuous free-fall since the early to mid-1960s. Its implosion accelerated after most of these denominations specifically liberalized their sexuality teachings over the last 20 years.

The facts of mainline Protestant decline are easily available. And yet the Mainline, once the dominant religious force in America, has declined so calamitously that for many it’s become almost forgotten. Often, when I speak to young people, I must explain what the Mainline is. Many young people, when they think of non-Catholic Christianity, are only familiar with Evangelicalism, which displaced the Mainline decades ago as America’s largest religious force.

[In summary], during the mainline implosion the percentage of Americans belonging to the seven sister denominations declined from one of every six Americans to one of every 22. If the Mainline had simply retained its share of population, it would stand today at about 55 million instead of about 16 million.

[It should be noted that] nearly all the mainline denominations have liberalized their sexuality standards over the last 15 years, precipitating accelerated membership loss. [Conversely], all growing denominations in America and the world are conservative on theology and on sexuality.

And [while] it’s true that the Southern Baptist Convention, the largest Protestant body, has been declining for 18 years, its decline from 16.4 million to 15 million represents an 8% loss, not comparable to the average Mainline loss of nearly 50%.

It’s important to reiterate the details of mainline Protestantism’s ongoing spiral as a warning to other churches. Whatever the problems of evangelical Christianity, becoming more like liberal Mainline Protestantism is not
a remedy.  

* Mark Tooley is president of Institute on Religion and Democracy ( This article is excerpted from IRD’s blog at