The turmoil of the 20th century proved a trying time for Christianity. Due to its global spread, there were Christians on all sides of nearly every major conflict of the century, from two world wars, through the use of nuclear bombs in Japan, to wars in Korea and Vietnam, to the anti-colonial conflicts in Latin America, North Africa, Sub-Saharan Africa, South Asia, and the Middle East. Marxist governments came to power and enforced secular culture throughout the historic areas of the Eastern Churches and in China. Christians were challenged to redefine their morals and their ideologies in response to these upheavals.
New movements emerged in the 20th century: ecumenism, liberation theology, Pentecostalism, and fundamentalism. Each in their own way represented a thoughtful response to the question of the role of Christians in the world. The 20th century also saw the development of a shift of a center of gravity to the global South.
The spirit of ecumenism is nearly as old as Christianity itself. The First Ecumenical Council at Nicaea in 325 was so called because bishops came from all parts of the Christian world. Twentieth-century ecumenism dates to 1910 when several missionary societies convened a meeting in Scotland designed to develop a common missionary strategy that could contribute to the healing of divisions and coordinate a mutual commitment to action and service to the world. Between 1910 and 1948, a number of denominations established international church councils. National church councils such as the British Council of Churches and the National Council of Churches of Christ in the U.S. were formed so that various Protestant groups could work together on issues of common interest. The World Council of Churches was founded in 1948.
The European experience of Nazism convinced the churches that the world needed a unified Christianity with the strength to resist further terrors. Over the next five decades, anti-colonial struggles and the resulting civil wars had a profound effect on the membership of the international federations and the World Council of Churches. Many of the member churches in the so-called first world built strong bonds of solidarity with churches in the developing world that were campaigning for national independence, self-determination, and economic development. These campaigns were tightly linked to a theology from the developing world called liberation theology. Liberationist movements found allies and partners in the ecumenical movement largely because of the increasing numbers of activists and intellectuals from the developing world in leadership roles in the federations and councils.
Beginning in Latin America, and emerging from local Christian responses to the conditions of extreme poverty and suffering, liberation theology called for all people to stand with Jesus on the side of the poor and the oppressed. Based in their practical experiences of combating illiteracy and helping the desperately poor to read the Bible, these theologians came to see the teachings of Jesus with new eyes. They saw fresh relevance in Jesus' love for the poor, and his efforts to ease their suffering. Latin American liberation theology was found in the scholarly writings of such teachers as Gustavo Gutiérrez and José Miguez Bonino, in the poetry and activism of revolutionary priest Ernesto Cardenal, in the work of literacy teacher Paolo Freire, and in the life and ministry of martyred Roman Catholic Archbishop Oscar Romero.
Liberation theology spread to the United States, where James Cone penned his A Black Theology of Liberation in 1970. Black liberation theology was furthered by the teaching and preaching of such American intellectuals as Cornel West and Dwight Hopkins, and transformed by women such as Jacquelyn Grant, Katie Cannon, and Delores Williams. Feminist liberation theology, African liberation theology, and Korean Minjung theology were among other compelling and inspiring explorations of incarnation and redemption. It was not long before liberation theologians began extending their ideas on human freedom and dignity to questions of environmental protection and health, as well as interfaith understanding and cooperation.