America's Protestant churches have their roots in the Protestant Reformation that began in 16th-century Europe, when Martin Luther, John Calvin and other clergymen and theologians sought reforms in the Roman Catholic Church. Their protests and theological writings — which attacked Catholic beliefs and practices such as purgatory, prayers to saints, devotion to Mary, the mother of Jesus, and the authority of the pope — spawned many new churches, the forerunners of Protestant churches today.
U.S. Protestantism has four main branches — evangelical, mainline, African-American and Peace churches.
Historically Black Denominations. Some Protestant churches with predominantly black congregations belong to mainline denominations or evangelical groups, but there are several historically black denominations. One early example is the African Methodist Episcopal Church, formally organized in 1816, whose original member congregations were established by slaves and former slaves who left integrated churches because of racial discrimination. Other historically black denominations include the African Methodist Episcopal Zion Church, the National Baptist Convention, USA and the Church of God in Christ, founded in 1907, which is considered the largest black denomination today.
Peace Churches. The three main Protestant peace denominations — Church of the Brethren, Mennonites and Religious Society of Friends, also known as Quakers — preach that Christ advocates non-violence and that his followers should do the same. Unlike other Protestant groups, they reject arguments that a "just war" is theologically possible.
Mainline Denominations. Unlike evangelical churches, all "mainline" churches are members of groups called "denominations." That makes them more "hierarchical" than most evangelical churches, says Laura Olson, a professor of political science at Clemson University in South Carolina.
Many denominations share a common liturgy among all member churches, such as a book of common prayer, Olson says. But in an age of consumer choice and individualism, the denominational, liturgical base of mainline churches may work against them.
"Mainline churches are very liturgical. They think if they create a really good worship service people will come," says James Davidson, a professor of sociology at Purdue University in West Lafayette, Ind. But that may put them at a disadvantage compared to evangelical churches, which "are very good at identifying what people need in spiritual life as well as in their family and social lives" and then finding ways to meet those needs, such as "establishing groups for people to discuss personal issues like divorce or being a woman executive in the work world." Davidson adds that mainline churches have been especially slow to tailor their activities to young people, such as switching church services to Sunday evening for a generation "that really doesn't believe you can function until it gets dark," he says.
But even in mainline churches, the key challenge for today's Protestants is the "breakdown of authority structures," says Michael Kinnamon, newly elected general secretary of the National Council of Churches.
"If ministers can be dismissed because the congregation doesn't like what they're saying," for example, "you . . . reduce religious values to mere opinions," he says. The question going forward is "how you speak with authority but also have dialogue."
Worldwide, there are as many as 9,000 separate Protestant groups, or denominations, but only a dozen or so sizable mainline denominations in the United States. The largest include: the United Methodist Church; the Evangelical Lutheran Church in America — organized in 1987 from the merger of three smaller Lutheran groups; the Presbyterian Church, which in 1983 reunited Northern and Southern branches that had split over slavery in the 19th century; the Lutheran Church — Missouri Synod; Episcopalians — descendants of England's national Anglican Church; Churches of Christ; American — or Northern — Baptists; and the United Church of Christ, which includes churches descended from the Congregational — Puritan — settlers of New England.
Evangelical Churches. In the evangelical world — which has the greatest number of U.S. members among Protestant churches — "you do have some denominations — like Southern Baptist," says Olson. "But congregations have a lot more latitude to do what they want," and many evangelical churches are independent. "The focus is on, 'Let's not do these practices just because we always have, but let the Holy Spirit' lead, "so you have a huge amount of diversity," she says.
The culture of evangelical churches also has "very powerful" and continuing appeal because "Americans like conversionary, uplifting religions," says Andrew Walsh, associate director of the Leonard E. Greenberg Center for the Study of Religion in Public Life at Connecticut's Trinity College in Hartford. The male-dominant nature of evangelical culture also secretly fosters "wild male behavior," such as excessive drinking, even as the pastors vigorously condemn it, Walsh says. "Liberal theology would reject that, saying, 'No, the answer isn't cracking down on people but educating them in the right' " behavior. But there's "a big audience for the conservative way," Walsh says.
Heavily evangelical denominations include the Southern Baptist Convention — the largest U.S. Protestant denomination — and the Assemblies of God, a Pentecostal church that embraces divine healing and "speaking in tongues" as a physical sign that worshippers have been baptized in the Holy Spirit.