The sight of war ruins is a common feature in Beirut’s landscape. The civil war (1975-1990) left behind an expansive geography of war-scarred ruins in Beirut and its peripheries. Amid a massive construction boom, skyrocketing land and housing prices, and high demand for building sites in Beirut’s immediate southern peripheries, the continued presence of ruins 25 years after the end of the war is puzzling. Based on an ethnographic study in the Hayy Madi- Mar Mikhail neighborhood, a peripheral area within the southern suburbs of Beirut, over two time periods (2003-2004 and 2010-2011), this essay examines the transformation of the geography of civil war’s ruins over time and its re-inscription within the unfolding sectarian conflict. Hayy Madi- Mar Mikhail neighborhood has become one of the major contested frontiers on which the Christians (through the Maronite Church) and the Shiites (through real-estate developers) are struggling over land. The study focuses on the doubleness of the ruins — as products of a past civil war and a present territorial war that is not-so-different from the civil war but using different tools — in the transformation of the area into a deadly sectarian frontier in “times of peace.” To do so, the paper examines locally the ways in which these two religious political organizations use urban planning, zoning, and buildings laws in their territorial battles. It also investigates the transnational networks of finance, fundraising, and religious allegiances that have shaped this Beirut periphery into sectarian frontiers mired with violence. The study elucidates how such transactions are defined by discourses of religious and sectarian differences with significant implications to ongoing conflicts locally and regionally. The paper argues that this transformation of Beirut’s peripheries to sectarian frontiers is shaped by what I call the spatial and temporal logics of the war yet to come through which religious-political organizations simultaneously calculate, govern, and manage the city’s urban growth and the their possible role in future local and regional wars. By analyzing complex hybrid urban actors -like Hezbollah or the Maronite Church- not simply as local, bounded actors, but also as embedded in global circulations of finance, real-estate, aid, ideologies, and conflict, this study rethinks methodologically the ways in which cities in the Global South are often conceptualized as a binary between the city’s center and its marginalized peripheries. Using Beirut as a case study, this study also illustrates how sectarianism is geographically produced, lived, and contested.