The Religion Guy confesses that, like so many writers, he has tended to depict U.S. Protestantism’s two-party system of “Mainline” vs. “Evangelical” mostly in terms of newsworthy LGBTQ issues. In more sophisticated moments, he might briefly note the underlying differences on Bible interpretation. But maybe something even more basic is occurring.

While scanning an important new research work, “The Twentysomething Soul: Understanding the Religious and Secular lives of American Young Adults” (Oxford), The Guy was gobsmacked by a graph on page 32.

You want news?

How about the prospect that U.S. Protestantism does not just involve that familiar biblical rivalry but could be evolving toward a future with two starkly different belief systems.

All U.S. religion writers and church strategists are anxiously watching the younger generation, and there’s been important research both here (care of Princeton University Press), here (make that Oxford University Press) and finally here (Oxford, again).

The project published as “The Twentysomething Soul,” led by authors Tim Clydesdale (sociology, College of New Jersey, clydesda@tcnj.edu) and Kathleen Garces-Foley (religious studies, Marymount University, kgarcesfoley@marymount.edu), surveyed an unusually large sample of Americans ages 20 to 30 and could fully categorize religious identifications, beliefs and practices.

The graph that grabbed The Guy involved who God is.

In this question’s option one, he is “a personal being, involved in the lives of people today.” Hard to think of a Christian belief more basic than that. In other options, God is “not personal, but something like a cosmic life force,” a fuzzy New Age-ish idea. Or God only created the world “but is not involved in the world now,” what’s known as Deism. Or the respondent lacked any sort of belief in God.

Just under 100% of Evangelical young adults — no surprise -- chose option one. But only half of those in “Mainline” churches affirmed this traditional belief, while for 40% God is some impersonal “cosmic life force.’” Catholics fell between the two Protestant categories. Even a sixth of “nones” without any religious affiliation believed in the personal, active God.

Or consider involvement in spiritual growth. Six out of 10 Evangelicals considered this “extremely” or ‘very” important for them personally, but only 3 out of 10 Mainliners (and the same for Catholics). There’s much more Mainline data, showing for example less daily prayer and weaker attachment to church than with other Christians.

The study says 14% of twentysomethings identify as Mainline, compared with 30% Evangelical, 29% “none,” 18% Catholic and 9% with other faiths. The authors predict that the Mainline segment will shrink by another 40% as of 2050 “unless some larger social disruption prompts hordes of conversions” and/or birth rates increase. “This will keep progressive Protestantism alive, but it will also result in shuttering a lot of Mainline church doors.”

A bleak scenario for the old-guard institutions that once dominated America's spiritual, moral and cultural life.

Journalists will want to know how Clydesdale and Garces-Foley defined their terms. “Mainline” refers to nine predominantly white, long-established denominations, in alphabetical order — the American Baptist Churches, Christian Church (Disciples of Christ), Episcopal Church, Evangelical Lutheran Church in America, Friends (“Quakers”), Presbyterian Church (USA), Reformed Church in America, United Church of Christ and United Methodist Church. (Confusingly, these groups include Evangelical sectors, and the “Evangelical” Lutheran body counts as non-Evangelical.)

The “Evangelical” category covered Protestants outside the “Mainline” groups who “hold to traditional teachings.” Many other sociological surveys treat members of historically black Protestant churches, so distinct in socio-political terms, as a separate category, but this study counted them as Evangelical on the basis of belief and practice.

The Guy has grabbed just one data point among many in this study, which religion specialists will want to contemplate and probably report on. The findings on Catholics or “nones” would also produce good articles.

The book’s over-all message is that despite unprecedented societal and economic disruption, growing secularism and the rise of “nones,” the coming generation is not as religiously adrift as many fear, another significant scenario summarized right here.