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 execute and implement in case of a general breakdown in civil order of the nation. Failure of the government to maintain control of civil affairs might have been caused by the Allied bombing of German cities, or uprising of the millions of foreign forced laborers working in German factories.
German Army 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 plan, designed to deal with internal disturbances in emergency situations, was designed by General Friedrich Olbricht's staff in his capacity as head of General Army Office and was approved by Hitler.
The key role in its actual implementation was played by Colonel Claus Schenk Graf von Stauffenberg, after his assassination attempt on Hitler on 20 July 1944. Stauffenberg also further improved the Valkyrie plan and made changes to address changing situations. Stauffenberg's position as Chief of Staff of the Reserve Army gave him access to Hitler for reports and at the same time required his presence at headquarters for implementation of Valkyrie. At first, Tresckow and Stauffenberg sought out other officers with access to Hitler who could carry out the assassination. General Helmuth Stieff, Chief of Organization in Army High Command, volunteered to be the assassin but later backed down. Tresckow attempted several times to be assigned to Hitler's headquarters without success. Finally, Stauffenberg decided to carry out both the assassination attempt and the Valkyrie operation, which greatly reduced the chance of success. After two abortive attempts, Stauffenberg placed the bomb on 20 July and hurried back to Berlin to assume his pivotal role.
Discovering that the bomb had not killed Hitler, Fromm ordered the executions of General Friedrich Olbricht, his chief of staff Colonel Albrecht Mertz von Quirnheim, Colonel Claus von Stauffenberg, and his adjutant Lieutenant Werner von Haeften. Shortly after midnight, the condemned men were led to a mound of earth back-lit by idling vehicles where each was executed by firing squad in the courtyard of Bendlerstrasse headquarters.