It's been confirmed in the kickstarter AMA part 2 that safe zone territory will be claimable:
What are the gameplay implications? Obviously the safe zones will be super valuable, but they won't be able to be fought over; only sold, right? Which means that the prime objective of all the starting players (with half a brain or more) will be to claim territory within the starting zone to either use strategically or sell to the highest bidder down the road. If the seat of a certain government is within a safe zone, can it ever be overthrown? If two orgs are at war and both are located within safe zones (possibly even the same safe zone), I suppose it could only become a war of attrition where they try to choke out each other's exterior supply lines? I'm just trying to fathom how this mechanic will affect societal development and organizational competition...