Armed group proliferation and conflict dynamics

How are conflict dynamics affected by contexts with many different actors compared with those dominated by a few? At the aggregate level, civil conflicts with many different rebels and militias experience higher levels of violence and human rights abuse, but the causal link between these two features remains underexplored. Are violent contexts particularly prone to organizational fragmentation or does the proliferation of armed groups lead to increased violence? This paper uses novel municipal-level monthly data from Colombia during 1975–2002 to investigate local conflict trajectories after additional non-state actors enter an area. Exploring both intrusion by (a) additional rebel groups and (b) anti-rebel militias, we find that increased militant competition leads to short-term increases in violence but that long-term trends depend on whether the “new” actors can access and form links with local social community networks.