I've had similar things happen, where one AI nation blockades my trade with another AI nation *FOR 20 YEARS* and the situation just sits their statically, with the victim making zero effort to free itself. Incredibly frustrating.

Frankly, I'd call the AI's failure to resolve AI-vs-AI wars (I'm including all on-going seiges, ally still at war with my now-ex enemy, etc.) in SOME fashion within SOME period of time to be the single most annoying strategic map level problem in the game (after CTD's, of course). I don't even care about "realistic results"- just roll the frickin dice and give me the outcome! Can C.A. put in some code so that each year, the odd's of a resolution to an AI-AI war increase by 10%, so that by year 10 we KNOW one side or t'other will have won, and we can get back to the game???

I don't post a lot, and I don't gripe in general- kinda love the game- but OP hit my sore spot...