Christian Nationalism has taken many forms over the years and certain versions of it are older than the United States itself. There was a widespread belief among Puritan settlers in the 1600s that they had a special covenant with God and were called to be an example to the world. From the founding of the country onward, some Christians believed that the United States was a “city upon a hill,” an idea that is often called “American exceptionalism.” But as Abram Van Engen points out, American exceptionalism is not the same as the Christian nationalism of “America First.” The paranoia and conspiratorial instincts of today’s Christian nationalism came about in the twentieth century in response to the same things that Trump attacks today, like global capitalism and international organizations.
Christian nationalism was widespread during World War I. It was heard in churches, universities, tent revivals, and in the military because American Christians so enthusiastically agreed with Woodrow Wilson that the war was a humanitarian cause to save Europeans from German aggression and to make the world more democratic. In 1918, evangelist Billy Sunday announced that the war was “Germany against America, Hell against Heaven.” Navy chaplain Henry Van Dyke added another verse to The Battle Hymn of the Republic, which was sung by American sailors during the war:
We have heard the cry of anguish,
From the victims of the Hun,
And we know our country’s peril
If the war-lord’s will is done
We will fight for world-wide freedom
Till the victory is won
For God is marching on
It took years for words like these to sound off-tune to American ears but, by the 1930s, many American Protestants had become embarrassed by their earlier belief that their nation was spreading Christian civilization throughout the world. They enthusiastically backed the League of Nations, a precursor to the United Nations. Pacifism suddenly became popular. Congressional committees investigated the causes of World War I and concluded that it was bankers and munitions dealers who led young Americans into needless slaughter in Europe. American Christians began taking more seriously the idea that there should be some separation between religion and nationalism.
In the 1930s, some American Protestants began, for the first time, to think about Christianity as a truly global community. Of course, they had sent missionaries abroad for years and spoke out against inhumane treatment of people overseas, but in the 1930s, they came to believe that the world was an intertwined whole, and they began to see global interdependence to be in conflict with nationalism.