The European Union faces a formidable constitutional challenge: it must decide over the distribution of power on two fronts. First, member states have to agree on how power should be separated within the organization. Second, the EU must balance the competing demands for increased centralization and decentralization. This book brings together scholars from economic and political science to study the interactions within the European Union from a strategic or rational choice perspective. The contributors seek out the logic of European institutions and identify possible hindrance to the creation of efficient and democratically legitimized institutions. Some focus on the horizontal check and balances including the countervailing forces of legislative, regulatory, bureaucratic and constitutional decision-making. Other examinations analyse the vertical structures, in particular the impact of the federal distribution of power on policy changes and their implementation.