Unitary State

A unitary state is one of the two principal models for vertically organising state power, the other being a federal state. In a unitary system, the central government is the sole source of sovereign authority. Any powers exercised by regions, provinces, departments, municipalities, or other subnational bodies are delegated by the centre and can, in principle, be modified or withdrawn by ordinary legislation or constitutional amendment at the national level.

This contrasts with federations such as the United States, Germany, or Brazil, where constituent units possess constitutionally entrenched competences that the centre cannot unilaterally strip away.

Unitary states vary widely in how much administrative power they devolve in practice:

• Centralised unitary states concentrate decision-making in the capital, with local authorities serving largely as administrative agents. France was historically a classic example, particularly under the Napoleonic prefectoral system.
• Devolved unitary states delegate substantial legislative or executive authority to subnational bodies while retaining the legal right to reclaim it. The United Kingdom is a frequently cited example: the Scottish Parliament, Senedd Cymru, and Northern Ireland Assembly exercise wide powers under the Scotland Act 1998, Government of Wales Act 2006, and Northern Ireland Act 1998, but Westminster retains parliamentary sovereignty.
• Regionalised unitary states such as Spain and Italy grant strong autonomy to regions or autonomous communities under the constitution, blurring the line with federalism without crossing it.

Most states in the world today are unitary. Examples include France, Japan, China, Indonesia, the Philippines, Egypt, Kenya (with devolved counties under its 2010 Constitution), Poland, and the Nordic countries.

For Model UN delegates and IR researchers, identifying whether a state is unitary matters when analysing treaty implementation, secessionist movements, or subnational diplomacy. Unitary states typically present a single, coherent foreign-policy voice, but devolution can complicate compliance with international obligations that touch on areas administered locally.