Don't stop them! Join them! Play as Korath Clan and exterminate everything standing in your way. I especially like to spore Torians - with their superbreeding worlds, they definitely need some sort of "population control".
Vortac
Tom Francis claims he put a spy on a Minor Race planet (Akilians). I don't think that's possible ("Let's not waste agents on Minor Races" or something like that). Also, he claims that the Korath declared war on Akilians although they didn't have any contact with them. I also think that's impossible (the usual reply I've seen is: "We have no contact with Akilians" or something like that)
Complex negotiations involving Trade Goods are obviously a pain in the neck for AI (in ToA, at least). For example, during negotiations I offer three techs in exchange for Economic Treaty. AI refuses (and rightly so). Then I offer the SAME three techs and ask for Economic Treaty AND Xinathium Hull Plating in return. AI all of the sudden agrees, although this is a far worse deal than the previous one which he refused. I play as Terran Alliance, with huge diplomatic bonuses, but this is obvious
DarkMadMax is right. Diplomacy is unbalanced and should be tweaked. AI is quite strong when trading techs (some techs are priced very high, others are not) and when trading resource starbases (which are NEVER for sale and that's realistic because they are really valuable). However, when negotiating wars and selling planets, AI is very weak. For a few techs, AI (especially Drengin and Korath) is willing to attack multiple civs at once, which in 20-30 turns can completely wreck its milit
My stupid AI story (DA 1.5, Gigantic map): I was at war with the Altarians and they sent a powerful fleet to destroy my isolated and already damaged resource starbase, which was additionally protected with 10-15 totally obsolete Defenders. When Altarian fleet has gotten close to the starbase, I disbanded my fleet and placed a single Defender in EVERY tile around the starbase. The Altarian fleet, unable to attack the starbase directly, just waited. They could have crushed ALL those Defen