The European Union (EU) is composed of its member states. The governments of those member states have signed and ratified successive Treaties outlining the objectives and institutions of the Union, starting with the European Coal and Steel Community of 1951 and continuing through the creation and institutional elaboration of today's European Union. As in any international organization, the member governments of the EU have assigned to themselves the central role in the governance of the Union. Member governments dominate both the European Council—the semi-annual summit meetings at which government leaders set the broad strategic direction of the Union—and the Council of Ministers, which has historically been, and remains, its pre-eminent legislative body. At the same time, however, the EU's member governments have created and allocated increasing powers and discretion to a number of supranational organizations, including the executive Commission, the European Court of Justice (ECJ), and a European Parliament (EP) which now acts as a co-legislator with the Council in a growing number of areas. Although clearly the creation, or agents, of the member governments, these supranational organizations possess powers and preferences distinct from those of their member-state principals, and they have frequently been posited by both practitioners and academic observers as the embodiment of the project of European integration, and indeed as the 'engines' or 'motors' of the integration process.
For the purposes of this book, the existence and activities of supranational organizations like the Commission, Court, and Parliament raise two sets of questions about the European Union and international organizations more generally. First, we can ask why, and under what conditions, do states create, delegate powers and allocate discretion to supranational agents, both within Europe and in international politics more generally. What functions do these and other organizations perform for the states that create them? How much discretion do member governments allocate to these organizations in the performance of their delegated powers? Do member governments deliberately design institutions to keep their supranational agents accountable, and, if so, how do they choose those institutions?