Mainline Protestant

Mainline Protestant (also sometimes called "mainstream American Protestant" and "oldline Protestant") is a group of Protestant churches in the United States contrasted with evangelical, fundamentalist, and charismatic groups. The group used to comprise a majority of all churchgoers in the United States in the early 20th century, but is now a minority even among Protestants. Mainline churches include the United Methodist Church (UMC), the Evangelical Lutheran Church in America (ELCA), the Presbyterian Church (U.S.A.) (PCUSA), the Episcopal Church, the American Baptist Churches, the United Church of Christ (Congregationalist), the Disciples of Christ, and the Reformed Church in America, among others.

Mainline churches share a common approach to social issues that often leads to collaboration in organizations such as the National Council of Churches. Because of their involvement with the ecumenical movement, mainline churches are sometimes (especially outside the United States) given the alternative label of ecumenical Protestantism. These churches played a leading role in the Social Gospel movement and were active in social causes such as civil rights and equality for women. As a group, the mainline churches have maintained religious doctrine that stresses social justice and personal salvation. Politically and theologically, contemporary mainline Protestants tend to be more liberal than non-mainline Protestants.

Members of mainline denominations have played leadership roles in many aspects of American life, including politics, business, science, the arts, and education, including founding most of the leading educational institutes in the US. Since the 1960s, however, mainline groups have shrunk as a percentage of the American population as increasing numbers of American Protestants have come to affiliate instead with fundamentalist, evangelical, or charismatic churches, or with no church at all. Mainline denominations peaked in membership in the 1950s and have declined steadily in the last half century. From 1960 to 1988, mainline church membership declined from 31 million to 25 million, then fell to 21 million in 2005. While in 1970 the mainline churches claimed most Protestants and more than 30 percent of the population as members, today they are a minority among American Protestants, claiming approximately 15 percent of American adults among their adherents in 2009.