Substates

Substates are political or administrative units within a sovereign state that exercise limited self-government or influence but do not possess full sovereignty. The term covers a range of entities, including provinces, states, cantons, regions, or municipalities, depending on a country's constitutional structure, as well as autonomous authorities that operate under a central government.

In constitutional arrangements, substates function within different legal orders. In federations, they typically have constitutionally defined powers and representation in government. In unitary states with devolution, powers can be transferred to regional authorities while sovereignty remains with the central state. The subsidiarity principle, central in the European Union, supports decisions being made at the most local level possible and shapes substate autonomy and intergovernmental cooperation. Common examples include Canada’s provinces; Spain’s autonomous communities; regions and municipalities in Italy; and Scotland, Wales, and Northern Ireland in the United Kingdom.

Substates may also refer to non-sovereign actors in international relations that influence policy, often through intergovernmental forums, cross-border cooperation, or regional diplomacy. The study of substates overlaps with subnational governance, regionalism, and nationalism, including movements seeking greater autonomy or independence. The term is distinct from 'subnational' or 'non-state' actors in some scholarly usages. In other disciplines, 'substate' arises as a shorthand for different concepts, and discipline-specific terms like 'substrate' are used for materials science and biology, where 'substate' is less common.