@konata_LS:
Here's the AI code. Based on that – no, not peace weight, but other personality values (build-unit prob, warmonger respect) that correlate strongly with peace weight. Also chance, SDI, number of owned nuke units and the "OWABWNW" AI strategy (short for "our words are backed by nuclear weapons", presumably). The decision about adopting OWABWNW is made
here, i.e. based on owning any nukes, on build-unit prob and on chance.
And, a few lines above the first link: Vassals support the master on "team votes" (leadership, diplo victory); for other votes, friendly attitude is needed.
Apparently, only voluntary vassals are forced to be friendly to their master. As for Tokugawa, the UI
displays only player-on-player attitude values, but the voting behavior – like war planning – is based on team-on-team attitude, which gets averaged for masters and their vassals. I'm guessing that Tokugawa doesn't like your other vassals enough.
So, all pretty arbitrary and obscure.
