The Night of the Long Knives (in German: Nacht der langen Messer, 29–30 June, 1934) was the Nazi purge of the Sturmabteilung (S.A.) leadership, and Hitler's political opponents; between 77 (official) and 400 people are believed to have been murdered.
The purge was the result of the political struggle between the Nazi leaders subordinate to Hitler: Hermann Göring, Joseph Goebbels, Heinrich Himmler and Reinhard Heydrich, on the one hand - and Ernst Röhm, the leader of the S.A., on the other. Hitler encouraged political infighting amongst his subordinates, and the power of Röhm and his violent organization scared his rivals. Himmler had evidence manufactured to defame Röhm and presented it to Hitler -- fuelling his suspicion that Röhm intended to use the S.A. to launch a putsch against him.
While Hitler had been personally rather fond of Röhm he was under pressure to reduce his influence. German military leaders were unhappy with Röhm's proposal that the German army be absorbed into the larger S.A., and the industrialists that supported Hitler were concerned over Röhm's socialist leanings. Members of the Nazi party also viewed Röhm and some other S.A. leaders with distaste because they were homosexuals.
With all these groups arrayed against Röhm, Hitler decided to act. He ordered all the S.A. leaders to attend a meeting at the Hanselbauer Hotel in Wiesse, near Munich. On June 29 Hitler arrived with a strong S.S force; he was present as Röhm was arrested, and in the following hours other S.A. leaders were also arrested, and many of these, were shot out of hand. Apparently Hitler intended to pardon Röhm, but eventually decided to have him die. It is believed that Röhm was offered a chance of suicide but was eventually shot.
On July 3, the Reich government decided upon the Law Regarding Measures of State Self-Defense, consisting of a single article simply declaring the "measures taken" to be "legal State self-defense."
Hitler announced the purge on 13 July, claiming 61 had been executed, 13 shot while resisting arrest, and 3 had committed suicide. In announcing the purge he stated, "If anyone reproaches me and asks why I did not resort to the regular courts of justice, then all I can say is this: In this hour I was responsible for the fate of the German people, and thereby I became the supreme judge (oberster Gerichtsherr) of the German people". - from William L. Shirer, The Rise and Fall of the Third Reich, Simon and Schuster, New York, 1959.
As a result of the purge, Hitler gained a measure of gratitude and support from the Reichswehr. On July 26th, the S.S. was made independent of the S.A., with Himmler as its Reichsführer, answerable only to Hitler. Victor Lutze became the new leader of the S.A., and it was soon marginalized in the Nazi power structure.
See also: Gleichschaltung