How did the movie Birth of a Nation add to racial problems in the South?
The film was released in 1915 and shows Blacks in in a negative way and the Klu Klux Klan in a positive way. It breathed new life into the dormant KKK.
The original KKK in the south was primarily groups of disgruntled former soldiers that began to take direct action against Blacks and Republicans. These groups were suppressed by the government after 1870 and the Klan became dormant.
Pretty much completely out of nowhere "Birth of a Nation" is released. The film touches on many underlying feelings and prejudices of white America of the time. Blacks are presented as uneducated, aggressive and sexually driven. The Klan is shown as heroic. By the 1920s the Klan had made a revival. The new Klan was anti Jew, anti catholic and anti immigrant as well as anti Black. It also was for prohibition and saw itself as a moral force against the decay of bootleggers. It was Protestant mostly but not supported by the mainstream Protestant Churches.
KKK costumes became and important fund raiser. The Klan spread across North America and became an important and vocal political movement. This would have revived the KKK in the South as it showed its strength an financial success there and elsewhere.
By the thirties the KKK had lost it momentum and membership fell dramatically. But the Klan was kept alive in places such as Birmingham, Alabama.