The Ku Klux Klan was active in the South during the 1930s on a much smaller scale than it had been in the previous decade, having reached its peak in 1925. It still threatened blacks to keep them from voting and were particularly active against trade union organizers. It was reported that the Klan were violent in their attempts to break up strikes, resorting to beating the picketers and going into the Union Halls with guns to break up the meetings.
The Ku Klux Klan that was organized after the Civil War spread a reign of terror on the blacks, carpetbaggers and scalawags in the South between five and fifteen years from 1865 to nearly 1880 when it was suppressed by actions of the Federal Government. After World War I it rose again with a vengeance. It grew rapidly all over the country in response to the labor force's perception that they were losing their jobs to blacks and immigrants.
Between 1923 and 1925 the Klan, at its peak, was able to dominate local politics and in some places packed the police with its own people. In one community, it was reported that on parade nights, traffic control was taken over by sheeted figures resembling the policemen.
During the later 1920s the Klan began to decline due to internal conflict, inept leadership, immorality and exploitation by the leaders. By 1929 the group that had boasted of a membership in the millions was reduced to thousands.
A section from Erskine Caldwell's, You Have Seen Their Faces (1937) takes a look at some of the reasons the Ku Klux Klan was so successful for a while.
In a land that has long been glorified in the supremacy of the white race, he directed his resentment against the black man. His normal instincts became perverted. He became wasteful and careless. He became bestial. He released his pent-up emotions by lynching the black man in order to witness the mental and physical suffering of another human being. He became cruel and inhuman in everyday life as his resentment and bitterness increased. He released his energy from day to day by beating mules and dogs, by whipping and kicking an animal into insensibility or to death. When his own suffering was more than he could stand, he could live only by witnessing the suffering of others.
This selection by R. A. Patton, writing about the activities of the Ku Klux Klan in "Current History" (1929), illustrates some of the atrocities that were committed by the Klan
A lad whipped with branches until his back was ribboned flesh: a Negress beaten and left helpless to contract pneumonia from exposure and dies; a white girl, divorcee, beaten into unconsciousness in her home; a naturalized foreigner flogged until his back was pulp because he married an American woman; a Negro lashed until he sold his land to a white man for a fraction of its value.
The Great Depression of the 1930s saw the Ku Klux Klan diminish to a fraction of its former self. Households barely had enough to eat so there were no funds for Klan dues and costumes. By the beginning of World War II the Klan was non-existent except in the minds of the former members.