2778.255 -- So far, we know the following about the Terrans:

1. The members of this conspiracy often carry pendants with a blue green yin yang symbol on them. The composition of the ceramic of the pendants is unusual. The pendants come from a place Dr Kye has never been.
2. The symbol on the pendant also appears in the artist's rendition in Jim's scout manual of the colonization of Ridena.
3. The purpose of the blue green yin yang pendants is to provide the wearer with an personal sense of community and purpose, and to serve as proof of membership on occasion, and to provide a visual reminder of what is at stake, what is being protected.
4. The conspirators want to destabilize the Linked Worlds, and to protect a blue-green planet, Terra.
5. The conspiracy has shown the ability to carry out well funded operations with lengthy preparations time or requiring agents in place for considerable amounts of time. (e.g. Donella's kidnapping)
6. The conspiracy has not simply severed the linked worlds by disabling the jumpgates.
7. "Tarn Alliance" has occasionally been written "Terran Alliance."

...and based on that, I think...

The Linked Worlds were originally settled from Terra, but there was a subsequent schism. They think they can (and need to) re-colonize the Linked Worlds at some point in the future and so want to keep the jumpgates intact. Whoever is in charge of the conspiracy is probably running things from within the linked worlds with limited local resources, thus the penchant for long quiet operations rather than throwing manpower at things.

> Er, can you clarify what I think that means?  re-colonize?  Do they
> expect us to wipe themselve out?

Could be.  It definitely strikes you that the plan would be to prepare
the area for recolonization as opposed to conquering.

> Do they want to conquer & recolonize?

You haven't had a sense of them having a big Conquering Plan yet, they
seem to be trying to turn you against each other instead.