The Continental Congress officially names its union of states the United States.

A political union is a type of political entity which is composed of, or created from, smaller polities or the process which achieves this. These smaller polities are usually called federated states and federal territories in a federal government; they are called prefectures, regions, or provinces in the case of a centralised government.

Unia w Krewie
Unia w Krewie (Source: Wikimedia Commons)

This form of government may be created through voluntary and mutual cession and is described as unionism by its constituent members and proponents. In other cases, it may arise from political unification, characterised by coercion and conquest. The unification of separate states which, in the past, had together constituted a single entity is known as reunification.

Signing of Declaration of Independence by Armand-Dumaresq, c1873 - restored
Signing of Declaration of Independence by Armand-Dumaresq, c1873 - restored (Source: Wikimedia Commons)

Unlike a personal union or real union, the individual constituent entities may have devolution of powers but are subordinate to a central government or coordinated in some sort of organization. In a federalised system, the constituent entities usually have internal autonomy, for example in the setup of police departments, and share power with the federal government, for whom external sovereignty, military forces, and foreign affairs are usually reserved.

Independence Hall
Independence Hall (Source: Wikimedia Commons)

The union is recognised internationally as a single political entity. A political union may also be called a legislative union or state union. A union may be effected in many forms, broadly categorized as:Incorporating union Incorporating annexation Federal union Confederal union Federative annexation Mixed unions

Watch: UNION | Official Trailer | POV on PBS

From the POV channel.

Sources and further reading: Wikipedia — Political union, Continental Congress (CC BY-SA). Images: Wikimedia Commons.