Someone on Facebook said something that crystallized my thoughts on how the various polities (nations for non-Travellers) treat and act toward each other. I decided that while they cooperate fully with each other when it comes to defending their polities against outsiders (especially the Alignment), when it comes to all other matters (especially the techcaches and jumpdrives) their relationship is analogous to the great Houses in Battletech.
Techcaches are the alien heuristic libraries discovered by each polity when it achieved the means to venture outside their atmosphere to the other planets, gas giants, and planetoid/asteroid belts in their star system. It gave up hints to advanced technologies in response to specific questions. Eventually this led the various research sophonts toward things like advanced computers, jumpdrives, fusion power plants, gravitonic technology, ecological machines, medicines, and more. The techcaches of each polity is their single most closely guarded secret, just above the jumpdrive technology.
The various polities can also be recognized by their ar’then or credo, and is as follows, Lemuria (House of Lore), the Federated Anvil (House of Iron), the Burning of Corix (House of Pain), the Concordium (House of Wind), the Unconfigured (House of Faces), and the Validine Pure Systems (House of Seasons). These credos will reflect some deep seated beliefs and psychologies that define who they are, how they act, and what their long term goals are.
As the polities expanded their borders, they achieved the borders they maintain today without adding more systems that were certainly within their reach. This seemed to happen at the same time, even though some of the polities are smaller than the others and would certainly have benefited from further expansion. Why they all agreed to stop at the same point in time is perhaps another mystery based on facts not evident to the common populace.