Immigration--The revival of the KKK combined anti-black sentiment with white nativist ideology. More immigrants meant more of a target for the group.
The KKK of the 1920s was not only anti-black but also added anti-Catholic, Jewish, and anti-immigrant to the ideology. Industrialization brought in many new immigrant groups which the KKK believed to be ruining the American culture (white culture). Blacks were also migrating North to obtain jobs, which made race relations a country issue not just a Southern issue.