Disengagement, the opportunists agitated, was long overdue; Earth inhabitants would never really understand what life in deep space was about.
The crisis came in the middle centuries. Bureaucrats representing the central government on Earth were isolated from the affairs of the colonies they administered. The indigenous populace ignored their authority, their credentials were challenged, and they were invited to return to their home planet — with no options.
The central government on Earth, weakened by shortages and distracted by agitators at home and in space, was neither vigilant nor prepared.
Early in the second millennium of the Interplanetary Era, several colonies in the Outer Region declared their independence of the original United Planetary System and of each other. Other colonies and outposts joined and within a decade, all had proclaimed themselves as newly constituted nation-states. Each reserved exclusive rights to negotiate with other nation-states of the Region. New agreements were implemented on matters of common interest, such as credits, industry, a judicial system, trade and commerce, science and technology, space traffic control, education and cultural exchange, and creation and management of infrastructure and management of life-support resources within their territories and jurisdictions.
The Outer Region's proclamations panicked the central government.
On the one hand, Earth ethicists argued, were the rights of the inhabitants of the space colonies. As members of distant societies they had modified their bodies, their environment and their cultures, therefore, they had a right to seek their own destiny unfettered by well-intentioned, but obviously impotent laws that originated on Earth. The advocates of this philosophy emphasized the Outer Region's right to their own physical, technological and cultural development. As unique civilizations, evolving at an unprecedented rapid pace, they were already radically different from the humankind that had remained on distant Earth.
On the other hand, claimed others, the system-wide scarcity of natural sources vital to the survival of the species was a shared crisis. The crisis could be solved, if at all, only through the most concerted application of humankind's intellectual and collective genius. In one context, they were indeed unique civilizations: robust, sophisticated and divergent, nevertheless, instinctively taking nourishment from a common fealty to humankind's ultimate destiny among the stars. Humankind would be far stronger and effective together, they argued, than it would be, divided within a common species.
The debate raged across the System. The separatists won.
Earth's General Assembly acceded to the demands for self-determination. The new status of the outer and inner regions was confirmed in The Treaties on the Separation of Jurisdictions for the Planets and Satellites of the Inner Region and the Independent Nations of the Outer Region.
The outer periphery of the Asteroid Belt became the boundary. The United Planetary System was dissolved and reconstituted as the United Inner Planetary System (UIPS). The natural and artificial colonies that orbited the planets and satellites of the Outer Region, or the central sun, retained their original identities (Ganymede, Titan, Callisto, etc.), and Pluto added "Planet" to its name to distinguish itself from planetary satellites. The former colonies beyond the Belt formed a loose federation: Independent Nations of the Outer Region (INOR).