In order to strengthen the position of the SS relative to the established German elites after a victorious war, SS chief Heinrich Himmler persuaded Hitler in late 1939 to permit the establishment of an armed SS force known as the Waffen SS. Although initially restricted to four divisions, the Waffen SS eventually fielded more than 20 divisions, putting half a million men under arms and establishing a command and operations structure to rival the German Army.
Also in 1939, Himmler established a separate SS disciplinary system, since neither civilian nor military courts had jurisdiction to investigate criminal acts perpetrated by members of the SS and police or their auxiliary units.
As military defeat reduced the prestige of the generals, the SS further encroached on the authority of the German armed forces (Wehrmacht). Already in 1942, the SS took over -- from the armed forces -- coordinating anti-partisan operations in the occupied Soviet Union. After the failure of the military putsch of July 20, 1944, Hitler appointed Himmler Commander of the Replacement Army (a position responsible for training and overseeing military personnel) and gave him command of matters relating to prisoners of war.