Progressive Christians are addressing disaffiliation — and a related, dangerous rise in loneliness among Americans — in a variety of ways. Mainline denominations are launching initiatives to plant new worshiping communities in all sorts of formats and places. The Emergent Church garners fewer headlines than it did a few years ago but hasn't disappeared. Some progressive (and some traditional) evangelicals hope that the Supreme Court's recognition of gay marriage will allow them to rally around new causes, while others contemplate following Rachel Held Evans out of Evangelicalism but deeper into the church.
From a qualitative perspective, these efforts are likely to be a breath of fresh air for American Protestantism. They also could soften negative attitudes toward Christianity that are especially prevalent among Millennials. From a quantitative perspective, though, I don't expect progressive Christian initiatives to alter any big trends. Deaths and defections will continue to shrink the mainline. Progressive evangelicals might, statistically, split the difference between rapidly declining liberals and the plateauing evangelical movement as a whole, or they might continue as a small, "moral minority." By the time the disaffiliated realize what has been lost in the decline of institutional Christianity — colleges and charities, elder and child care, art and architecture, social capital and the social safety net — it may be, as it appears to be in England, too late. Cultural victory seems hollow in the face of that kind of defeat.