In the case of an alliance à trois, is there a way to determine which side the mutual ally will join?
For instance, as The Palatinate, I am currently allied with Wurttemberg, but so is Alcase. If I declare war on Alcase, is there a way to know which side the mutual ally will throw in with? If so, is there a way to influence that decision?
I thought it may be based on which side they liked more, but I had my rep at 200 with them and they decided not to join. Is it based on the reason for the war, relative power, or something else entirely?