Since the 1950s, European integration has seen the development of a supranational system of governance, as its institutions move further from the concept of simple intergovernmentalism and more towards a federalized system. However, with the Maastricht Treaty of 1992, new intergovernmental elements have been introduced alongside the more federal systems, making it more difficult to define the European Union (the EU). The European Union, which operates through a hybrid system of intergovernmentalism and supranationalism, is not officially a federation – though various academic observers regard it as having the characteristics of a federal system.