Steve -
The situation is as follows:
Homeworld population, 1.34 billion, requested protection level=742, actual protection level = 864
Old HW commander stats: Political Reliability=35, research=15, mining=30, and various combat related bonuses.
New HW commander stats: Political Reliability=20, Factory Prod=15, Pop Growth=25, Diplomacy=30
Everything was fine, I was sailing through year 27, when something started happening that I didn't understand. I replaced the commander of the homeworld with a new commander (as above). I immediately noticed that the HW's political stability modifier (PSM) began decreasing by a small amount every time advance (.0103 per five days). Nothing else changed that I noticed (although it is always possible that something changed that I didn't notice). The PSM steadily decreased every time advance, for no discernable reason.
As noted above, the HW has enough protection, so I can't figure out what is going on. Is the PSM tied to commanders in some way?
Kurt