What if the Nazi government get the idea, that in order to keep the U.S. out of the war it starts to infiltrate the KKK in the South in the late 1930s? And get them to start a campaign of insurgency against the federal government in the South? This uprising keeps the US out of the war until mid 1942, and the U.S. witness treason trials resulting in high-level clan leaders (including officials and elites from the South sentenced to death for treason. Pearl Harbour stills happens, and the U.S. enters into Europe in 1943 instead of 1942. History still goes as planned however, and Hitler kills himself in Berlin in january 1946, and Japan is defeated in April 1946 do to atomic bombs being dropped on the country.
Only difference between this and OTL is that there is a military presence in the southern states like Arkansas, Mississippi and Tennessee. And now the whole movement is tarnished by the clan being traitors to the nation. How could that effect Jim Crow and parts of Southern US?