The aim of this work was to examine how the complex racial question of American South was solved following the Union win in American Civil War. The victory of the Union meant the collapse of the slave system that was widespread across the American South, the system that was meant to be replaced by new postwar system in which blacks would be equal with whites. Assuming that the ratification of the 13th Amendment of the U. S. Constitution laid the foundations for integration of the black population, the author analyzes the legislative acts and examines the social changes that marked the period of Reconstruction. In the first part, the author uses comparative analysis to analyze the black codes and other legislative acts, such as pre-war slave laws and the U. S. Constitution, in order to point out what rights were conferred to the black population as well what rights were denied to them. In the second part, the author explains the origin of the Ku Klux Klan and it's role in solving complex racial issue. Furthermore, the author explains in which way the federal government dealt with said organisation. In the last part of his work, the author analyzes federal laws in order to demonstrate how the (victorious) federal government in Washington D.C. approached the integration of newly freed part of the population and through which legislative procedures they achieved territorial integrity of the United States.