Nacht und Nebel ([ˈnaχt ʊnt ˈneːbəl]) was a directive issued by Adolf Hitler on 7 December 1941 targeting political activists and resistance "helpers" to be imprisoned or killed, while the family and the population remained uncertain as to the fate of the offender.
The alliterative hendiadys Nacht und Nebel (German for "Night and Fog") was first used by Wagner in Das Rheingold (1869) and has since been adopted into everyday German (e.g. it appears in Thomas Mann's Zauberberg). It remains unclear whether the term Nacht-und-Nebel-Erlass had been in wide circulation or used publicly before 1945.
Even before the Holocaust gained momentum, the Nazis had begun rounding up political prisoners from both Germany and occupied Europe. Most of the early prisoners were of two sorts: they were either prisoners of personal conviction (belief), political prisoners whom the Nazis deemed in need of "re-education" to Nazi ideals, or resistance leaders in occupied western Europe. Up until the time of the Nacht und Nebel decree, prisoners from Western Europe were handled by German soldiers in approximately the same way as other countries: according to international agreements and procedures such as the Geneva Convention. Hitler and his upper level staff, however, made a critical decision not to conform to what they considered unnecessary rules and in the process abandoned "all chivalry towards the opponent" and removed "every traditional restraint on warfare."
On 7 December 1941, Reichsführer-SS Heinrich Himmler issued the following instructions to the Gestapo:
After lengthy consideration, it is the will of the Führer that the measures taken against those who are guilty of offenses against the Reich or against the occupation forces in occupied areas should be altered. The Führer is of the opinion that in such cases penal servitude or even a hard labor sentence for life will be regarded as a sign of weakness. An effective and lasting deterrent can be achieved only by the death penalty or by taking measures which will leave the family and the population uncertain as to the fate of the offender. Deportation to Germany serves this purpose.