In irregular civil wars, armed groups strategically aim to conquer, preserve and control territories. Local civilians inhabiting these territories respond in a wide variety of forms. Although the two dominant responses seem to be to collaborate with the strongest actor in town or flee the area, civilians are not stuck with only these choices. Collectively defying armed groups by engaging in organized nonviolent forms of noncooperation, self-organization and disruption is another option. However, given unequal force, it is still unclear why ordinary unarmed civilians choose to defy fully...