The Nazis removed citizenship from German Jews then, during the Second World War, sent most Jews, from Germany and elsewhere, to camps outside the borders of pre-war Germany. Yet, as the war progressed, Germany brought in huge numbers of forced labourers from all over Europe (U.S. Attorney General Jeff Sessions’ claim that German-run camps were designed to keep Jews in, rather than out, is unfounded).
His strategy proved successful; at a special party congress on 29 July 1921, he replaced Drexler as party chairman by a vote of 533 to 1. The committee was dissolved, and Hitler was granted nearly absolute powers as the party's sole leader. He would hold the post for the remainder of his life. Hitler soon acquired the title Führer ("leader") and after a series of sharp internal conflicts it was accepted that the party would be governed by the Führerprinzip ("leader principle"). Under this principle, the party was a highly centralised entity that functioned strictly from the top down, with Hitler at the apex as the party's absolute leader. Hitler saw the party as a revolutionary organisation, whose aim was the overthrow of the Weimar Republic, which he saw as controlled by the socialists, Jews and the "November criminals" who had betrayed the German soldiers in 1918. The SA ("storm troopers", also known as "Brownshirts") were founded as a party militia in 1921 and began violent attacks on other parties.
Heinrich Himmler's Schutzstaffel (SS) took full control of the police and the concentration camps throughout Germany in 1934–35. Himmler expanded the role of the camps to hold so-called "racially undesirable elements", such as Jews, Gypsies/Romanis/Sintis, Serbs, Poles, disabled people, and criminals. The number of people in the camps, which had fallen to 7,500, grew again to 21,000 by the start of World War II and peaked at 715,000 in January 1945.