In the Summer of 1927 the Austrian Social Democrats remained powerful despite their history of collaboration with the government. In response to the acquittal of the murderers of a worker and his 8 year old son Viennese workers came out in force, in a series of riots. Fearing a revolution the Social Democratic party called a general strike and used its powerful Socialist Republican Guard to police the workers and keep them off the streets.
This history of the event has been written by a pacifist and so views this betrayal as a positive development.