The European Union may, with profit, be regarded as a qualitatively new type of security organization, one that seeks to create cooperation and harmony through a high level of economic and political interdependence. Whereas NATO remains at heart a military organization, the EU defines its security concerns in terms of an ever widening "sphere of affluence", rather than a classical "sphere of influence." This distinction is more than just a play on words: it underscores the importance of economics and trade as the current basis for stability and democratic development. Although EU member states pursue what they still imagine to be their "national interests", already those interests are essentially reduced to rather modest policy preferences, constrained within a tightly bounded multilateral framework. A myriad of treaty commitments now limits the room for maneuver of European states and locks them into dense networks of activities created by institutional and political decisions. It is these sunken costs of European integration that preclude "sovereign" member states from tearing up the Union's founding treaties, packing their bags, and returning to a policy of national autarky.
The EU has transformed once proud and sovereign nation-states beyond recognition, changing their role and place both in Europe itself and in the world at large. A wide range of traditionally national prerogatives is now either pooled collectively or shifted to the supranational (or federal) level. Whereas the 1648 Treaty of Westphalia inaugurated a European system of autonomous states, the 1991 Maastricht Treaty has de facto ended any hopes of saving that system.