What happens to wartime forms of peace-promoting civilian organizing after conflict ends? This thesis investigates whether wartime civilian organizing shapes patterns of postwar retaliatory violence, engaging two bodies of literature that have rarely been studied together. I develop a theory of Civilian Peace Infrastructure, arguing that sustained cross-cleavage civilian organizing reduces retaliatory violence through the formation of prosocial trust, the disruption of collective blame attribution, and the channeling of grievances into nonviolent forms. Drawing on a typology of organizing configurations differentiated by durability and cross-cleavage character, the thesis derives six hypotheses tested in Syria through a nested mixed-methods design combining district-level quantitative analysis across all 65 Syrian administrative districts with twenty key informant interviews conducted across Syria’s three wartime territorial orders. While the quantitative findings identify no statistically significant relationship between organizing and postwar retaliatory violence, the qualitative analysis finds evidence of the proposed typology and, following a model-building logic, identifies four processes that disrupted the anticipated mechanisms: the opening of vertical political channels, elite reconstruction of collective blame frameworks, the erosion of economic infrastructures sustaining cross-cleavage interaction, and the nationally scaled encounter of organizational cultures formed in territorial isolation. Transitional justice emerges across these dynamics as the absent structural intermediary. The findings frame the policy challenge less as one of reconstructing civic agency from the ground up than of institutionally reactivating the normative residues generated through wartime organizing and preserving the conditions under which they can endure.