Supranational assurance: how European Union membership clears the way for political decentralization in countries with secessionist potential

Political decentralization is in vogue. However, it is not clear what political incentives central governments should have to give up authority. Thus, the question guiding this thesis is under what conditions and why central governments shift authority to subunits. The existing literature does not specify the cost-benefit calculus that could underlie such a decision, merely viewing decentralization as a reaction to increased demands for subnational authority, which are believed to be the result of international trends such as Europeanization or globalization. Working with a sample of 42 industrial democracies that have been observed over a period of up to 40 years, I demonstrate that central governments pursue institutional reforms only under the condition that they are sufficiently reassured that granting autonomy to subunits will not threaten the territorial integrity of the nation-state. When this necessary condition is met, as is shown to be the case for European Union member states, state agents are mainly motivated by reaping the political benefits associated with reforming a malfunctioning political system or with accommodating sub-national demands.