In his 1986 article Philip Bosshardt argued:
We have seen that cultural divergence works against federation. Barring unforseen developments in relativistic physics, settlements will never be in instant communication with each other. Message flow may resemble more the speeds of royal message runners in the Persian and Incan empires, taking minutes if not hours to traverse the distances between settlements. Modern technological societies could scarely function without the ability to shift huge volumes of information nearly instantaneously; without up-to-date information on events in the “provinces,” no ruler of trans-Solar System empires is going to know if his directives are being carried out. And at the other end of the chain of command, local governors will be reluctant to cede power to a ruling body that cannot have very good knowledge of current conditions. (Bosshardt, 1986).
This passage makes it clear that Bosshardt is talking about trans-Solar System federations or empires. The size of the Solar System is simply to large to unite it under one single political entity. However, this is no argument against small and local space federations. In fact, it is likely that many future Space nation will be federal states.
What is federalism?
Like many political terms federalism has different meanings in different situations. In the United States of America, federalism is mostly used for the movement or ideology which favours a stronger position of the national government. But in other countries such as Belgium or Spain, federalism stands for the opposite idea: transferring power from the national government to sub-national governments.
If we say that Republic of Lagrangia endorses federalism, we mean that we favour the creation of a federal state or federation. A federation is a state based on the principle of shared sovereignty: on some issues the federal governments has exclusive authority, whilst other issues belong to the exclusive domain of the states. Typically foreign policy, defense and inter-state relation are under federal authority.
Why does this matter for space settlements?
Because of their nature, Space habitats will be the fundamental political units of Space society. Space settlements are, in a physical sense, closed systems. The residents of a Space habitat can if they wish relocate their territory. A luxury not available to the people of, say, Pennsylvania.
This fact has important consequences for inter-settlement politics. When, for instance, Colorado and Utah have an intense conflict with each other, they are nevertheless forced to deal with each other. If, however, two Space settlements has a similar dispute either habitat can decide to relocate away from the other.
Individual Space settlements enjoy a greater factual sovereignty than US states or even members of the European Union. However, many Space settlements will be rather small, having a population from a few thousand to several hundred thousands. Therefore many settlements will be dependent from each other. For economic reasons, most settlements will specialize in specific goods or services whilst importing other from other settlements.
Regulation required by inter-settlement trade will be among the primary reasons of creating a federation of Space habitats. Further small Space habitats will have difficulties with setting up a proper defense force, by uniting themselves they will be able to manage a proper military. Also by creating a federal government Space people can pursue a more effective foreign policy, especially in relation with terrestrial nations.
One or multiple Space federations?
A single Space federation is impracticable for the reasons given by Philip Bosshardt, the Solar System is simply too big. For these reason alone, there will be multiple federations each in a different part of our Solar System. However, distance is not the only reason for multiple federation.
Since different people have different political ideologies. Therefore different Space settlements will implement different political and social systems. Socialist settlements will most likely prefer to federate with other socialist settlements, whilst libertarian settlements will federate with other libertarians.