Unitary state in the context of "Communities, regions and language areas of Belgium"

A state is a political entity that regulates society and the population within a definite territory. Government is considered to form the fundamental apparatus of contemporary states.

A country often has a single state, with various administrative divisions. A state may be a unitary state or some type of federal union; in the latter type, the term "state" is sometimes used to refer to the federated polities that make up the federation, and they may have some of the attributes of a sovereign state, except being under their federation and without the same capacity to act internationally. (Other terms that are used in such federal systems may include "province", "region" or other terms.)

A federation (also called a federal state) is an entity characterized by a union of partially self-governing provinces, states, or other regions under a federal government (federalism). In a federation, the self-governing status of the component states, as well as the division of power between them and the central government, is constitutionally entrenched and may not be altered by a unilateral decision, neither by the component states nor the federal political body without constitutional amendment.

Sovereign power is formally divided between a central authority and a number of constituent regions so that each region retains some degree of control over its internal affairs.

The Government of Japan is the central government of Japan. It consists of legislative, executive and judiciary branches and functions under the framework established by the Constitution of Japan. Japan is a unitary state, containing forty-seven administrative divisions, with the emperor as its head of state. His role is ceremonial and he has no powers related to the Government. Instead, it is the Cabinet, comprising the prime minister and the ministers of state, that directs and controls the government and the civil service. The Cabinet has the executive power and is formed by the prime minister, who is the head of government. The Prime Minister is nominated by the National Diet and appointed to office by the Emperor. The current cabinet is the Takaichi Cabinet, which is led by prime minister Sanae Takaichi, who assumed office on 21 October 2025. The country has had a Liberal Democratic minority government since 2025.

The National Diet is the legislature, the organ of the Legislative branch. The Diet is bicameral, consisting of two houses with the House of Councilors being the upper house, and the House of Representatives being the lower house. The members of both houses of the Diet are directly elected by the people, who are the source of sovereignty. The Diet is defined as the supreme organ of sovereignty in the Constitution. The Supreme Court and other lower courts make up the Judicial branch and have all the judicial powers in the state. The Supreme Court has ultimate judicial authority to interpret the constitution and the power of judicial review. The judicial branch is independent from the executive and the legislative branches. Judges are nominated or appointed by the Cabinet and never removed by the executive or the legislature except during impeachment.

Regionalism is a political ideology that seeks to increase the political power, influence and self-determination of the people of one or more subnational regions. It focuses on the "development of a political or social system based on one or more" regions, and/or the national, normative, or economic interests of a specific region, group of regions or another subnational entity, gaining strength from or aiming to strengthen the "consciousness of and loyalty to a distinct region with a homogeneous population", similarly to nationalism. More specifically, "regionalism refers to three distinct elements: movements demanding territorial autonomy within unitary states; the organization of the central state on a regional basis for the delivery of its policies including regional development policies; political decentralization and regional autonomy".

Regions may be delineated by administrative divisions, culture, language and religion, among others. Regionalists' demands occur in "strong" forms (such as sovereigntism, separatism, sovereignty, secession and independence), as well as more "moderate" campaigns for greater autonomy (such as states' rights, decentralization or devolution). Strictly speaking, regionalists favour confederations over unitary nation states with strong central governments. They may, however, embrace intermediate forms of federalism. Proponents of regionalism usually claim that strengthening the governing bodies and political powers within a region, at the expense of a centralized government, will benefit local populations by improving regional or local economies, in terms of better fiscal responsibility, regional development, allocation of resources, implementation of localist policies and plans, competitiveness among regions and, ultimately, the whole country, consistent with the principle of subsidiarity.

A centralized government (also united government) is one in which both executive and legislative power is concentrated centrally at the higher level as opposed to it being more distributed at various lower level governments. In a national context, centralization occurs in the transfer of power to a typically unitary sovereign nation state. Executive and/or legislative power is then minimally delegated to unit subdivisions (state, county, municipal and other local authorities). Menes, an ancient Egyptian pharaoh of the early dynastic period, is credited by classical tradition with having united Upper and Lower Egypt, and as the founder of the first dynasty (Dynasty I), became the first ruler to institute a centralized government.

All constituted governments are, to some degree, necessarily centralized, in the sense that even a federation exerts an authority or prerogative beyond that of its constituent parts. To the extent that a base unit of society – usually conceived as an individual citizen – vests authority in a larger unit, such as the state or the local community, authority is centralized. The extent to which this ought to occur, and the ways in which centralized government evolves, forms part of social contract theory.

Devolution is the statutory delegation of powers from the central government of a sovereign state to govern at a subnational level, such as a regional or local level. It is a form of administrative decentralization. Devolved territories have the power to make legislation relevant to the area, thus granting them a higher level of autonomy.

Devolution differs from federalism in that the devolved powers of the subnational authority may be temporary and are reversible, ultimately residing with the central government. Thus, the state remains de jure unitary. Legislation creating devolved parliaments or assemblies can be repealed or amended by central government in the same way as any statute. In federal systems, by contrast, sub-unit government is guaranteed in the constitution, so the powers of the sub-units cannot be withdrawn unilaterally by the central government (i.e. not without the process of constitutional amendment). The sub-units therefore have a lower degree of protection under devolution than under federalism.

A central government is the government that is a controlling power over a unitary state. Another distinct but sovereign political entity is a federal government, which may have distinct powers at various levels of government, authorized or delegated to it by the federation and mutually agreed upon by each of the federated states.

The structure of central governments varies. Many countries have created autonomous regions by delegating powers from the central government to governments on a sub-national level, such as regional, state, provincial, local and other instances. Based on a broad definition of a basic political system, there are two or more levels of government that exist within an established territory and government through common institutions with overlapping or shared powers as prescribed by a constitution or other law.

Federalism is a mode of government that combines a general level of government (a central or federal government) with a regional level of sub-unit governments (e.g., provinces, states, cantons, territories, etc.), while dividing the powers of governing between the two levels of governments. Two illustrative examples of federated countries—one of the world's oldest federations, and one recently organized—are Australia and Micronesia.

Johannes Althusius (1563–1638) is considered the father of modern federalism, along with Montesquieu. In 1603, Althusius first described the bases of this political philosophy in his Politica Methodice Digesta, Atque Exemplis Sacris et Profanis Illustrata. By 1748, in his treatise The Spirit of Law, Montesquieu (1689-1755) observed various examples of federalist governments: in corporate societies, in the polis bringing villages together, and in cities themselves forming confederations. In the modern era Federalism was first adopted by a union of the states of the Old Swiss Confederacy as of the mid-14th century.