While the member states are sovereign, the union partially follows a supranational system for those functions agreed by treaty to be shared. ("Competences not conferred upon the Union in the Treaties remain with the member states"). Previously limited to European Community matters, the practice, known as the 'community method', is currently used in many areas of policy. "Combined sovereignty" is delegated by each member to the institutions in return for representation within those institutions. This practice is often referred to as 'pooling of sovereignty'. Those institutions are then empowered to make laws and execute them at a European level.