One of the stars on the map I was playing with CPUs on was contested by me, one ally, and two enemies, both of which were allied only with people on another star. I notice that somehow my Diplomacy level is rising with one of these enemies, even though I've been fighting both of them actively the entire game, and we even made a trade pact. Funny that it should happen, my ally makes a peace treaty with that same enemy. Now even though these two especially were hard at each others necks this entire time, and meanwhile she's bombing a planet of mine, but he'll only fight with pirates and the other guy.
This bothers me. Not just because they allied with each other- but because they were at war this entire game, and he stops supporting me and makes a cease fire with one of our enemies. We had the advantage-it would have have made a lot more sence to kill them both off and take the entire star system for ourselves. I don't expect the CPU to have thought that out, however, I do feel that this is somewhat of a loop hole. If an ally of mine is allied with an enemy, it doesn't seem quite right that me and my enemy keep fighting while he completely ignores us both and sits it out.
Let me chuck my idea out there- if me and a CPU start out allied, shouldn't someone need to ally with both of us in order to achieve a cease fire? Suppose we share the same Diplomacy level with him, or we both need to agree on the cease fire pact first. Say, when I offer the cease fire pact, it will show my allies hands, too and the majority of them would need to agree to it. Not everyone I have a cease fire pact with would suddenly need to agree to it, I imagine. Maybe only allies with the Peace treaty agreement? This would give some insentive to be picky about who I ally with, instead of just sending envoys out and excepting every pact that comes in and letting the CPUs kill each other off.