From Think on These Things, Mar/Apr 2016. Essentially the same article also appears in Voice magazine. Read Part 1.
The Second Great Divide
The colossal differences between liberals and conservatives were crystallized around the turn of the century with the subsequent division of the two camps occurring in the 1920s and 1930s. At this point the conflict was often referred to as the Fundamentalist-Modernist controversy but, as the years rolled by, another division was looming, this one among the Fundamentalists.
By the 1940s the question of cultural and social engagement had arisen within the Fundamentalists’ camps. The original Fundamentalists, perhaps oversensitive to the social gospel that was at the heart of liberalism, often pushed away from any form of social action. In time, some felt that they had gone too far and needed to become more involved with the culture and improve society, as well as preach the gospel.
This ultimately led to a split within the conservative camp. The Fundamentalists would take on more separatist views, that is, they would separate from any who taught false doctrines and, rather than try to infiltrate society, they would live as lights of the gospel calling people to Christ. On the other hand, the opposing position would be termed new (or neo) evangelical. Read more about Biblical Fundamentalism, Part 2