state

A state is a political entity that asserts exclusive sovereignty over a defined territory and its population. It is typically endowed with institutions such as a government, a judiciary, and security forces capable of enforcing laws and policies. In international law, a state is recognized as a subject of international relations, with the capacity to enter treaties and to engage with other states.

States may be organized as unitary states, where most governing power is centralized, or as federations, which distribute authority to subnational units. Examples of federal states include the United States, Germany, and Canada; examples of unitary states include France and Japan. The balance of power between central and regional authorities varies across systems and can be altered by constitutional provisions and political events.

Beyond politics, the term state has other meanings. In physics and chemistry, a state refers to the condition of a system (for example, solid, liquid, gas) or the oxidation state of an element. In computing and mathematics, a state describes a particular configuration of a system, such as a state in a finite-state machine or a stateful program.

Within public policy, the state is the central actor responsible for maintaining order, providing public services, enforcing laws, and safeguarding national security. The concept of the welfare state emphasizes state involvement in social provision, economic regulation, and redistribution.

History and theory of the state examine its origins, legitimacy, and evolution from early centralized authorities to modern nation-states and supranational organizations. Debates continue over sovereignty, state capacity, and the balance between centralized power and regional autonomy.