Post-war reactions and reflections
Conservatives, nationalists and ex-military leaders began to speak critically about the peace and Weimar politicians, socialists, communists, and Jews were viewed with suspicion due to their extra-national loyalties. It was rumored that they had not supported the war and had played a role in selling out Germany to its enemies. These November Criminals, or those who seemed to benefit from the newly formed Weimar Republic, were seen to have "stabbed them in the back" on the home front, by either criticizing German nationalism, instigating unrest and strikes in the critical military industries or profiteering. In essence the accusation was that the accused committed treason against the "benevolent and righteous" common cause.
These theories were given credence by the fact that when Germany surrendered in November 1918, its armies were still in French and Belgian territory. Not only had the German Army been in enemy territory the entire time on the Western Front, but on the Eastern Front, Germany had already won the war against Russia, concluded with the Treaty of Brest-Litovsk. In the West, Germany had come close to winning the war with the Spring Offensive. Contributing to the Dolchstoßlegende, its failure was blamed on strikes in the arms industry at a critical moment of the offensive, leaving soldiers without an adequate supply of materiel. The strikes were seen to be instigated by treasonous elements, with the Jews taking most of the blame. This overlooked Germany's strategic position and ignored how the efforts of individuals were somewhat marginalized on the front, since the belligerents were engaged in a new kind of war. The industrialization of war had dehumanized the process, and made possible a new kind of defeat which the Germans suffered as a total war emerged.
Nevertheless, this social mythos of domestic betrayal resonated among its audience, and its claims would codify the basis for public support for the emerging Nazi Party, under a racialist-based form of nationalism. The anti-Semitism was intensified by the Bavarian Soviet Republic, a Communist government which ruled the city of Munich for two weeks before being crushed by the Freikorps militia. Many of the Bavarian Soviet Republic's leaders were Jewish, a fact that allowed anti-Semitic propagandists to make the connection with "Communist treason".
http://en.wikipedia.org/wiki/Dolchstosslegende