Hitler did not come to power by election. In November 1932 the Nazi Party (NSDAP) won 33.1% of the Reichstag vote — not a majority, but the largest single bloc. What actually opened the door was the Weimar Republic's chronic coalition crisis and elite manipulation. Former chancellor Franz von Papen, believing Hitler could be 'kept under control,' persuaded President Paul von Hindenburg to appoint him chancellor. Only three of eleven cabinet ministers were Nazis. Within six months that calculation collapsed.

On the evening of 27 February 1933 the Reichstag building burned. A young Dutch communist, Marinus van der Lubbe, was arrested at the scene; he was probably acting alone, but the Nazis used the conspiracy claim. The Reichstag Fire Decree issued the next day suspended basic civil liberties; communist deputies were arrested. The Enabling Act (Ermächtigungsgesetz) passed in March 1933 gave the government legislative power — the authority to amend the constitution without parliament. In July 1933 all parties except the NSDAP were banned. When Hindenburg died in August 1934, Hitler merged the chancellorship and the presidency: Führer und Reichskanzler.

The regime's ideological core was a fusion of fascism, antisemitism, and pseudo-scientific racism. The 1935 Nuremberg Laws stripped Jews of German citizenship and outlawed interracial marriage. In November 1938 the Kristallnacht ('Night of Broken Glass') attacks burned synagogues, looted Jewish property, and sent tens of thousands to camps. In parallel the regime took control of every domain of social life through Gleichschaltung ('coordination'): trade unions, universities, churches, the press, the arts, youth organisations. Disabled people were killed between 1939 and 1941 under the T4 Euthanasia Programme — a technical rehearsal for the genocide that would follow.

Foreign policy was revised at the same pace. Conscription returned in 1935; the Rhineland was remilitarised in 1936; Austria was annexed in 1938 (Anschluss); Czechoslovakia's Sudetenland was handed over by the Munich Agreement. On 1 September 1939 the invasion of Poland began the Second World War. From 1941 onward, the systematic killing of Jews across occupied Eastern Europe — the Holocaust — reached industrial scale at camps including Auschwitz, Treblinka, Sobibór, and Bełżec; six million Jews and millions of Roma, gay people, disabled people, political opponents, and Slavic civilians were murdered. Nazi Germany stands as historical proof of what happens when the bureaucratic, technical, and scientific instruments of the modern state are placed at the service of an ideology. That lesson has been the core of the next eighty years of debate on human rights, genocide law, and liberal democracy.