IE:
If the Terrans are allied with the Drengin and the Yor, all they need
to do is either ally with you, or wipe you out to win. The Drengin and
the Yor would be losers as well in this case, and both should be
striving to keep you from allying with the Terrans, but keep you alive.
Yes, this is exactly the kind of situations i meant... also.
Diplo-Victory is a tricky case for a number of reasons;
1- Any AIs must keep tab on any **human** nearing a win-status IF they think a flipped Alliance may reverse to their advantage -THEN, maintain the balance of power to stop anyone (incl other AIs) from stacking the deck at a winning % through Alliances -ELSE, declare war or upscale their Diplomatic-ratings through
other means.
2- Eliminating the weakest(s) at the appropriate moment can cause a HUGE tilt in favor of allianced race-
S, IF the total edges at the necessary percentage while the winner (be it human or otherwise) took a backdoor step to create such a condition.
3- It isn't that far off from a clear Influence victory too, strategy-wise.
4- Getting somebody (specially AIs) high enough in the Close/Friendly mindsets to allow for Alliance treaties requires a
LOT of assets and thoughts... plus a whole bunch of patience if not, outright luck. Thus - the algorithms certainly have a specific routine to evaluate these very things.
5- Any AI which is even enough to the human player status would do almost anything to prevent a victory. Alliances included - unless.(!)

Sums it up to me.
- Zyxpsilon.