Borders and boundaries can represent old narratives, which often, however, cannot deal with new realities. Borders are inflexible, but reality is flexible and fluid. This is augmented in crisis situations. Multi-ethnicity and history run in parallel, as shared cultures often precede and transcend Westphalia and institutionally imposed borders. For cultures with roots in antiquity, top-down established borders appear to lack legitimacy, as these cultures place more emphasis on historical similarities and traditions of peoples. Thus, what is more important: cultural and historical commonalities or institutional top-down constructions? This article examines the impact of the prioritization of top-down ethno-religious homogeneity over lasting conflict resolution. Through an interdisciplinary approach, the article draws a number of hypotheses from the fields of conflict resolution, territoriality, and nation building and tests these hypotheses on the specific case of the 1923 Compulsory Population Exchange (CPE) between Greece and Turkey and the dual role of the Mediterranean as a security bridge or barrier. This article highlights a “how-not-to” scenario in conflict resolution and argues that efforts to form apparent homogeneous nation-states led to short-term, incomplete conflict termination with a lasting impact, while conflict resolution remained elusive.