Operation Valkyrie (German: Unternehmen Walküre) was a German World War II emergency continuity-of-government operations plan issued to the Territorial Reserve Army of Germany to implement in the event of a general breakdown in national civil order due to Allied bombing of German cities, or an uprising of the millions of foreign forced labourers working in German factories.
German Army (Heer) officers, General Friedrich Olbricht, Major General Henning von Tresckow and Colonel Claus von Stauffenberg modified the plan with the intention of using it to take control of German cities, disarm the SS, and arrest the Nazi leadership once Hitler had been assassinated in the 20 July plot. Hitler's death (as opposed to his arrest) was required to free German soldiers from their oath of loyalty to him (Reichswehreid). After lengthy preparation, the plot was activated in 1944, but failed.
The original operation
The original plan, designed to deal with internal disturbances in emergency situations, ensured combat readiness of units among scattered elements of the Reserve Army. It was developed by General Friedrich Olbricht's staff in his capacity as head of General Army Office and was approved by Hitler. However, apart from Hitler himself, only Colonel-General Friedrich Fromm, Chief of the Reserve Army since 1938, could initiate Operation Valkyrie.
Coup-oriented revisions
The idea of using the Reserve Army in the German homeland to unseat the Nazi regime had existed before, but Fromm's refusal to cooperate in a prospective coup posed a serious obstacle to the conspirators. Nevertheless, after the lessons of a failed assassination attempt on 13 March 1943, Olbricht felt that the original coup plan--which anticipated a more spontaneous uprising--was inadequate and that the Reserve Army should be used even without Fromm's cooperation.
The original Valkyrie order only dealt with combat readiness of Reserve Army units.