Social Terrain and Conflict Diffusion: Civilian Networks and the Spread of Territorial Control in the Philippines

Abstract

This paper examines how “social terrain” shapes cascading changes in territorial control during insurgent conflicts, with a focus on civilian social networks as a key factor driving conflict diffusion. Using large-scale data from the Philippines—including village-level military intelligence reports on insurgent presence, government development projects, and the network of family ties between 55 million individuals in 40,000 villages—I find that the government was more likely to secure new territory when civilians had social ties to other villages already under government control and benefitting from development projects. Drawing on field interviews, I propose that these networks primarily drive the diffusion of territorial control by serving as conduits for information about security and economic interests, which in turn shapes patterns of civilian cooperation with conflict actors. These findings underscore the importance of civilian social networks in shaping territorial control in civil conflicts.