This paper presents a theory of insurgency-state strategic interaction based on the insurgency’s mode of survival. The theory postulates that, ceteris paribus, illegal resources discourage the insurgents from desiring to control the state and the state from regaining control of the insurgent territory, whereas legal lootable resources “force” the insurgency to embrace the suboptimal strategy of trying to topple the government, while causing the state to desire full control of the insurgent territory. Intensity, the number of combatant deaths over time, will be used to test the theory. Civil conflicts involving insurgencies that rely on illegal resources for most of their revenue should be of low intensity. The opposite should hold true for civil wars in which the insurgency’s livelihood is a legal lootable resource.