The 1866 Ku Klux Klan had the goal of "restoring white supremacy". They were motivated by the newly enfranchised black freedmen. They performed acts of violence against black people until Congress passed the Force Acts in 1870, which protected the constitutional rights guaranteed to blacks by the Fourteenth and Fifteenth Amendments; and the Ku Klux Act in 1871, which empowered the President to suspend the writ of habeas corpus to combat the Ku Klux Klan.
By this time, the Klan had practically disappeared because they had achieved their original objective.
The resurgence of the Klan during the 1920's was fueled by patriotism and romantic nostalgia for the old South. But, mainly, it expressed the defensive reaction of white Protestants who felt threatened by the Bolshevik revolution in Russia and by the large-scale immigration of the previous decades that had changed the ethnic character of American society.
This new Klan included the old Klan's hostility againts black people along with new biases against Roman Catholics, Jews, foreigners, and organized labour.
The new clan reached a membership of over 4,000,000 nationally, developed a symbol (a burning cross) and participated in marchs and nighttime cross burning all over the country.