A transformation of political violence? Substitution and complementarity in terrorism and civil war

There is a widespread perception that terrorism has increased over the last two decades, and common data on terrorism appear to back this up. This raises questions about the relationship between terrorist tactics and other types of political violence. Some argue we see a transformation of political violence, where indirect targeting through attacks on civilians replace conventional civil conflict where non-state actors directly target the state and security forces. We examine the relationship between terrorism and civil war in terms of potential substitution or complementarity between tactics, moving from trends in aggregate data over time to disaggregated analyses focusing on specific non-state actors and relative allocation of direct and indirect targeting. We find little evidence consistent with strict substitution, or growth in indirect attacks in countries outside episodes of civil war, but more evidence consistent with growing complementarity between terrorism and civil war, with increased use of terrorist attacks within civil wars over the period where terrorism appears to have increased. We examine whether increased use of terrorism in civil war coincides with observable changes in the characteristics of ongoing civil wars, and find increasingly asymmetric conflicts where rebels may benefit more from carrying out terrorist attacks.