When Lebanon gained its independence from France in 1943, it adopted a system that divided political power along clearly defined sectarian lines. The institutionalized sectarian nature of the country resulted in tensions that led to civil war in 1975. Lebanon quickly disintegrated into a number of irreconcilable cantons and seemed to be destined for a perpetual state of war. After 15 years of conflict a compromise was forged that, while not resolving the institutionalized sectarian tensions at the heart of Lebanon's problems, was successful in bringing the fighting to an end and maintaining peace. This article discusses how the trajectory of Lebanon's economic and social development after independence, the 15-year civil war that almost destroyed the country, and the agreement that ultimately ended that war all provide a basis for understanding the nature of institutionalized sectarianism in the modern world and the kinds of conflicts and compromises that such sectarianism is likely to engender. [This paper is a Senior Division Historical Paper from the National History Day 2018 Competition.]