I find the easy method of defeating the AI with either side with any settings by mid1862 is to occupy in force an important location such as Alexandria, Bowling Green, etc.; then sit back and watch the AI attack over and over again each turn with major losses until a Morale Victory is won.
Is there a combination of settings that prevents the AI from continuously attacking when it is killing itself off? I assume AI Aggressiveness on low would be the first step; yet I expect an AI with Low Aggressiveness would still attack these key site while doing nothing else.
Any advice?