Last year, Gallup reported that, for the first time in the nation’s history, most Americans don’t belong to religious congregations. This was a landmark moment in a long and familiar story: America is becoming less religious, and its many declining religious communities are the clearest sign of this cultural transformation.

Many people on the Left welcome the decline of religious affiliation in the United States. They point to the fact that religion is often “co-opted in sustaining the status quo for poor and politically subjugated groups,” as Megan Rogers and Mary Ellen Konieczny write. As followers of the so-called Prosperity Gospel blame poverty on impiety and corrupt megachurch pastors pad their pockets at the expense of working-class parishioners, it’s easy to see their point. Yet the decline of religious affiliation has also had profound drawbacks for the Left, contributing to a lack of community structures among leftists that often leaves them unable to organize people behind their causes and political candidates.

Historically, religious congregations were a vital site of left political organizing. Following the successes of the civil rights movement, which was spearheaded by pastors and other religious voices, Rev. Dr. Martin Luther King, Jr. organized religious leaders behind a radical program for economic justice. Before that, the Social Gospel movement of the late nineteenth and early twentieth centuries was instrumental in galvanizing support for legislation that created an eight-hour workday, abolished child labor, and improved factory conditions. The leaders of the Social Gospel movement, including Rev. Washington Gladden and Rev. Mark A. Matthews, were not only authors and lecturers but also congregational leaders, actively organizing their local communities in support of these social reforms.