For decades the dominant story of postwar American religious history has been the triumph of evangelical Christians. Beginning in the 1940s, the story goes, a rising tide of evangelicals began asserting their power and identity, ultimately routing their more liberal mainline Protestant counterparts in the pews, on the offering plate and at the ballot box.

But now a growing cadre of historians of religion are reconsidering the legacy of those faded establishment Methodists, Presbyterians and Episcopalians, tracing their enduring influence on the movements for human rights and racial justice, the growing “spiritual but not religious” demographic and even the shaded moral realism of Barack Obama — a liberal Protestant par excellence, some of these academics say.

After decades of work bringing evangelicals, Mormons and other long-neglected religious groups into the broader picture, these scholars contend, the historical profession is overdue for a “mainline moment.”

As one commenter put it on the blog Religion in American History, “It’s heartening that dead, white, powerful Protestants are getting another look.”...