2. Will a coalition dissolve after several years of peace, even if the members have over 100 AE against the target? When?
a coalition member can only LEAVE a coalition 2 years after joining. So a fresh coalition won't immediatly disband, but can if members leave after their 2 year period. This can create cascade effect of everyone leaving.
It's a secret formula that serves for the AI to estimate their own strength vs their target, it has never been broken up (as a matter of fact, even the possibly more simple rivalry system has not been uncovered).
(copy pasted from coalition guide in signature)
there are some things that one can say for sure on this topic...
Military rating evaluates the
land warfare capabilities of a country.
Modifier Rating
Mil Tech
+0.2 per Technology level.
Mil ideas
+0.1 per idea +
+0.25 per bonus.
Generals
+0.025 per pip for each general or conquistador (counting rulers/heirs). Max
5.00.
Military quality
+0.15 per +5% combat ability (sum of all types).
Discipline
+0.15 per +5%.
Standing army unknown effect
Morale of armies
+0.5 per point.
War exhaustion
-0.2 per point.
I tested it, and I found out army maintenance slider plays a role.
If you lower it, the coalition can declare faster. Got that idea from a DDRJake stream, where coalition declared the day AFTER he lowered army maintenance.
Which led to the theory now, that it is in fact military rating that AI looks at( combined with ongoing war enemy strength), when deciding to declare coalition war or not. Because military rating goes DOWN if you lower maintenance slider.
The basic rule for AI ATTACKING takes your allies and subjects forces/military rating into account also, and your current wars.
If you declare on major alliance web, expect a big coalition to form the next week, if it didn't before. The reverse is also true, if you get OUT of a big war after coalition formed, it might actually disband.
So, if 1. you and your allies are fighting a BIG war together, or 2. if you lower army maintenance or delete troops, coalition becomes more eager to attack you, if they have more troops etc.
You can observe power of coalition when you are at peace by using 'Threaten War' UI.
One of the factors used in calculation is a "Relative coalition power". This is dependant on military rating most likely. You can do some tests by using console. Just start non-ironman game as e.g. Ottomans (they have cores in foreign nations at the beginning of the game - no need to fabricate).
- For the nation to leave coalition their strength must be lower than 10% (around 5-6%). Strength measured in Threaten War view.
- The coalition will attack if their strength is greater than 100% (usualy >120%)
One more way to assess your military strength is to use rivals setting window - there you have it specified in one, concise number, relative to your potential rivals. it is certainly not perfect method but gives you some insight.
You can play with it and see it changes with your manpower quantity, army maintenance level, technology level, morale/discipline bonuses etc.
I suppose some console testing might shred some light on all this..