Superstate

A superstate is defined as "a large and powerful State formed when several smaller countries unite", "A large and powerful state formed from a federation or union of nations". This is distinct from the concept of superpower, although these are frequently seen together. It is also distinct from the concept of empire, where one nation dominates other nations through military, political, and economic power, although an empire may also be a superstate.

In the early 20th century, "superstate" had a similar definition as today's supranational organisations. In a 1927 article by Edward A. Harriman on the League of Nations, a superstate was defined as merely "an organisation, of which a state is a member, which is superior to the member themselves", in that "[a] complete superstate has legislative, executive and judicial organs to make, to execute and to interpret its laws". According to this definition, Harriman saw the League of Nations as a "rudimentary superstate", and the United States as "an example of a complete and perfect superstate".

In World Order of Bahá'u'lláh, first published in 1938, Shoghi Effendi, the Guardian of the Bahá'í Faith, described the anticipated world government of that religion as the "world’s future super-state" with the Bahá'í Faith as the "State Religion of an independent and Sovereign Power."

In the 1970s, academic literature used the term "superstate" to indicate a particularly rich and powerful state, in a similar fashion to the term superpower.

In contemporary political debate, especially the one centred on the European Union, the term "superstate" is used to indicate a (usually deemed unwelcome) development in which the Union takes over the character of a State (including the monopoly on violence) thus abolishing the sovereignty and independence of its member states. For instance, Glyn Morgan opposes the perspective of a "European superstate" to the ones of "a Europe of nation-states" and of "a post-sovereign European polity". In her definition, a "European superstate is nothing more than a sovereign state - a tried and tested type of polity that predominates in the modern world - operating on a European wide scale", i.e., "a unitary European state"

...
Wikipedia