The civil war in South Sudan has claimed the lives of more than 50 000 people and displaced millions. South Sudan formally became independent in 2011, descending into civil war soon thereafter. Debates about the future of South Sudan have always included federalism as a mechanism to foster peace and development. The 2011 Constitution, meant to be transitional, is federal in nature and explicitly recognizes ‘devolution‘ and ‘decentralization‘ to accommodate the ethnic, cultural, linguistic, religious and racial diversity of the South Sudanese people. Yet, these federal features did little to prevent the human catastrophe currently unfolding in South Sudan. This paper focuses on what there is to learn from the process of constitution-building as well as the content and implementation of the 2011 Constitution. What are the key factors, both legal, political and social that undermined the federal features of the peace agreement? What role can federalism play in the future of South Sudan?