Used both for the hierarchal structure of the legal instruments of a nation (or of a multinational federation such as the European Union), usually as set by the Constitution or treaty, and for overviews of the organization and operation of those institutions, including legislatures, courts, and executive agencies. This term is used primarily for materials descriptive of entire national or multinational legal structures or regarding major alterations of the national system. For changes to lesser parts of a system, such as by reorganization of executive agencies or reassignment of their responsibilities, use GOVERNMENT ORGANIZATION.