This paper aims to contribute to our understanding of the significance of the role that international aid organizations and the United States played in housing provision and urban planning during the Cold War in Lebanon, and as the country geared up to the 1958 uprising followed by a fifteen-year civil year war (1975-1990). It does so by tracing the tenuous relationship between development and planning discourses, and highlighting the corresponding shifts in approaches to housing provision and ordering of territories. This paper illustrates how these shifts in logic coincided with global moments of anxiety around communism, and later, political Islam. It also shows how eventually spatial practices were eventually transformed through militias’ and religious-political organizations’ spatial interventions into a collection of innovative design and planning exercises aimed at balancing the spatiality of a sectarian order. It highlights how this shift in the approach of planning from the quests and questions of development centered on issues of poverty to an exercise in spatializing sectarian difference changed the discourse around Beirut’s southern peripheries from that of informal and poor peripheries to sectarian frontiers. The paper illustrates how this reformulation of the political consciousness vis-à-vis the periphery, its economy, marginality, and inhabitants has had major repercussions on poverty, segregation, violence, and environmental degradation.