Left wing extremism (LWE) in Australia between 1968 and 1972 has been described inconsistently as either unstructured terrorism or protest activity. Schmid’s (2012) work on defining terrorism was applied to this case study to try to sharpen the blurred lines between these two forms of political mobilisation. It is argued that while most LWE activity was protest activity, there were instances where the activity constituted terrorism due to its premeditated nature, risk to life, and threat-based communication. This has application to contemporary left wing activism in Australia and around the western world. Further examination of LWE mobilisation also demonstrates that the actors were likely organised in free-floating cells, capable of cooperation, but otherwise autonomous, thus establishing a precedent for left wing leaderless resistance. This challenges the notion that organisational decentralisation is a new element to contemporary terrorism.