1: European Security, Integration Theory and Boundaries -- 2: Federalism and Security through Boundaries -- 3: Europe as a Power: Boundaries Solidified -- 3: Europe as a Power: Boundaries Solidified -- 4: Functionalism and Security without Borders -- 5: Security Governance: Boundaries in Flux -- 6: The EU, Russia and the War in Ukraine -- 7: Integrating Integration Theories: Towards the Future Research Agenda.

This book examines federalism and functionalism - two fundamental, yet largely forgotten, theories of international integration. Following the recent outbreak of the war in Ukraine, policy practitioners and scholars have been in search of a deeper understanding of the likely causes of the conflict and its consequences for the European security architecture. Various theories have been deployed to this end, but international and European integration theory remains conspicuously absent. The author shows how the core tenets of integration theories developed after World War I, particularly how they viewed territoriality and geopolitical boundaries, remain as relevant today as they were almost 100 years ago. Kamil Zwolski is Associate Professor in International Politics at the University of Southampton, UK.