The following excerpts come from Eric P. Kaufmann’s book The Rise and Fall of Anglo-America and illustrate the degree to which the rise of Modernism was transforming American Christianity in the first three decades of the 20th century.
In the early 20th century, American Protestantism became obsessed with ecumenicism and cosmopolitanism and began to splinter. Cultural pluralism was developed by Horace Kallen, William James and especially by John Dewey around the turn of the 20th century. By the 1920s, the American Protestant establishment was committed to liberal cosmopolitanism.
The American Protestant establishment, which had become committed to liberalism, cultural relativism, cosmopolitanism and modernism between 1900 and 1920, was ferocious in its opposition to the Second Klan which was supported by lay Protestants in the 1920s.
This was a major shift.
The American Protestant establishment began to associate missionary work with imperialism. They lost their self confidence around 1910. Protestant elites began to disassociate Christianity from Western civilization. This was due to the growing influence of cultural relativism, liberalism, modernism and cosmopolitanism around the turn of the 20th century.
The impact of Modernism on American Protestantism in the early 20th century was so enormous that it fractured the mainline churches from the 1920s.
The American Protestant establishment opposed the Immigration Act of 1924.
What is the point of all this?
It shows how the Zeitgeist seizes control of people and takes them into its grip and how all of human society is ultimately remolded around it. Interestingly, the divide that opened up in the 1920s which has worked itself out over time was between Protestant elites and lay Protestants rather than between Protestant denominations or between Catholics and Protestants. There is a similar divide between Catholic elites and lay Catholics which also became committed to ecumenicism.
Note: The fault line that Modernism has opened up runs within nations. See also the rural/urban divide. In contrast, Romanticism set nations at odds with each other over territorial claims.