If I may insert myself.
But I have to agree this is BattleMaster not PoliticsMaster.
'War is a continuation of politics by other means.'
There's no neat segregation here. War is politics and vice versa.
If your realm has enough CS you crush the one that will benefit you the most. You don't really need a reason. I mean They don't even make one in the real world anyway. Just like how USA attacked Afghanistan and Iraq.
The USA happens to be a superpower, and a nuclear armed one at that. The rules are different for it than they would be for medieval powers. You DO need a reason, or at least reason enough to convince the people you need to convince.
