This book offers a foundational rethinking of how international law engages with non-state effective territorial entities - territories that, while legally part of a recognised state, are de facto governed by non-state actors or other states.

These entities - ranging from ISIL-controlled areas in Syria to the contested territory of Crimea, the autonomous Somaliland, and Taiwan - occupy an increasingly prominent place in global politics, yet remain inadequately addressed in legal doctrine.

Rather than assessing these territories through the binary lens of statehood, the book begins by assuming their non-state status and asks: what legal capacity and responsibilities do such entities hold under international law? It considers their obligations toward both other states and the populations under their control, and explores the broader implications for concepts like sovereignty, territorial integrity, and recognition.

Drawing on four case studies across a spectrum of state-likeness, the book moves beyond isolated analyses of conflict or self-determination to offer a more holistic account of what these entities reveal about the limits and possibilities of the current international legal framework. It argues for a more functional, capacity-based understanding of legal responsibility that acknowledges the realities of territorial control without forgoing the notion and role of statehood.

Combining doctrinal clarity with pragmatic ambition, this book challenges the state-centric foundations of international law and offers a roadmap for engaging with one of its most pressing contemporary challenges: the legal accommodation of non-state territorial authority in a world still structured around states.