A unitary system is a form of government in which authority is concentrated in the central government. Local governments, such as those of regions or cities, are under the control of that central authority. They have only those powers granted to them, and the central government may alter or abolish local authorities at will. This distinguishes this type of system from the government of a federal state, in which the federation's constituent units themselves have at least some attributes of a sovereign state in their own right that the federal government must respect, and from confederations, in which sovereign states voluntarily delegate certain powers to a supranational organization.
This system is the world's most common form of government, and it appears in both democratic and nondemocratic countries. Most European nations have unitary governments — with the exceptions of Belgium, Germany, Switzerland, Bosnia-Herzegovina, Austria and Russia — as do most of Africa and Asia. Most governments based on the Westminster system are unitary, though Canada, Australia, India and Malaysia have federal constitutions. Present-day monarchies where the monarch still has significant power, such as Liechtenstein, Qatar and Saudi Arabia, usually are unitary, though the United Arab Emirates is a federation ruled by an elective monarchy. Dictatorial and single-party governments almost always are unitary, though the defunct Federal Socialist Republic of Yugoslavia was an exception to this.
The central government in a unitary system is responsible for managing national-level concerns, such as foreign relations, national defense and national economic policy. The central ruler or decision-making body controls all aspects of governance, because there are no powers or functions legally reserved to other levels of authority. All areas of government ultimately are under the authority of a single body, so states that have this type of system often have more uniform laws and regulations than federations. The central government also might be responsible for appointing the personnel of lower levels of government, such as regional or provincial governors.
Government decisions in unitary states are not necessarily made by the central authority. Some unitary governments delegate some degree of decision-making power to more regional or local authorities in a process called “devolution,” which often is instituted to accommodate ethnic or linguistic minorities who desire greater autonomy. In the United Kingdom, for instance, the Northern Ireland Assembly, the National Assembly of Wales and the Scottish Parliament have legislative powers for their respective regions. These bodies were created and their powers defined by the Parliament of the United Kingdom. Parliament has the power to abolish these bodies or to increase or decrease their powers as it chooses, and the constituent countries of the United Kingdom have no sovereignty of their own.
Other examples of devolution within such a system include the five autonomous regions of Italy and Papua New Guinea's regional and provincial governments. An extreme case is Spain's system of autonomous communities, which remain officially subordinate to the national government but have extensive powers and account for most government spending. Spain sometimes is regarded as a country that straddles the border between a unitary system and a federal state, because many of the regional governments have more authority within their territories than states in most officially federal forms of government do, and the political entrenchment of the autonomous regions would make it extremely difficult for the central government to abolish them despite officially having the power to do so.