In this paper I propose a mechanism for the explanation of power-law characteristics of casualty dynamics in inter-state wars, intra-state wars and terrorist attacks: the scale-free physical organization of social systems. Other explanations - self-organized criticality (Cederman, 2003) and the redistribution of total attack capabilities (Johnson et al. 2006) - do not provide a consistent framework for the power-law characteristics of casualty dynamics. The development in time of the power-law characteristics of casualty dynamics during wars and conflicts provides clues for the functioning of social systems which are targeted, and/or for the (in)effectiveness and strategies of actors using force (violence) against these social systems.