I don't know what to say other then in my game the AI does not get to choose before me but i think thats the benefit of being the faction leader or something ai_accept, Ai always accepts whatever you ask, i think that might do something or the AI in your game is more agressive then iv yet seen. i also tried just passing as you suggested but the problem is that other nations dont pass they take states so i really dont know what to do its really pissing me of i like the game a lot but this peace conference stuff really killed the game for me. i did fight in the war i have like 40% war effort so i have a second best warscore around 2240 first have 2250 but ai is just terrible at territory choosing so i need some way to get around it and get the world i want.
