What leads armed groups to continue fighting, even in the face of extensive attempts at negotiated settlements or imposed military solutions? The rich information available on the activities of armed groups contrasts with few systematic explanations of this behavior. Systematic models, in turn, often fail to account for the environment in which armed groups operate. This project proposes a new theory of civil war duration and termination that combines the systematic with in-depth knowledge of conflict. How actors benefit from opportunities that exist only during conflict explains duration and termination of conflict. During wartime, actors exploit opportunities unavailable to them under conditions of peace. Wars continue when, conditional on survival, actors remain able to exploit these unique opportunities. The theory suggests that policy-makers concentrate resources on activities that choke off the collateral benefits to conflict. The policy implications of this theory diverge from the predictions of the credible commitment view of war termination prevalent in the literature and policy circles. The theory of wartime opportunities will be investigated through field research on the Lebanese Civil War (1975-1990) using parallel qualitative and quantitative strategies: interviews with ex-combatants and civilians and compilation of a disaggregated database on the conflict. The multiple dimensions of warfare and political issues at play in Lebanon allow the project to examine in one conflict what researchers would have to explore in many separate conflicts. The research design also explicitly generalizes findings from the fieldwork by placing the Lebanese Civil War in context using cross-national data and other national studies and by an analysis of the conflict in Northern Ireland. This work fits into a larger research agenda that aims to generate and test a better theory of the dynamics of civil wars that can explain outcomes during conflict and their effects on the post-conflict situation. Current explanations of civil war termination in the literature are likely incorrect because of their heavy reliance on the assumption that an inability to credibly commit to a future settlement drives actors to continue fighting. By proposing an original theory of war termination which does not rely on credible commitment, this project changes how scholars in International Relations and Comparative Politics understand civil wars. The rigorous empirical test of the theory through fieldwork and comparative analysis will advance the field of study. The project's policy implications will also contribute to policy debates on civil war termination and post-conflict stability. The project's fieldwork involves substantial partnership with the academic community in Lebanon. Lebanese graduate and undergraduate students will be hired as research assistants (RAs) for the database and interview portions of the fieldwork. RAs will be trained and work closely with the co-principal investigator, integrating education and research. Publication of the project's results in Arabic will help to disseminate the findings and extend the research's impact beyond academic circles in the United States and Lebanon to Lebanese society, as will workshops and presentations in Lebanon in addition the U.S. The project's emphasis on the policy implications will provide substantial benefits to society. The goal is to improve the ability of policy-makers to limit the devastating effects of internal warfare and build post-conflict stability.