Relations and alliances
Every state has an opinion of every other (RelationRelationMechanicOne state's opinion of another (−100 to +100). It influences alliances, crises and whether offers are accepted.). It drifts monthly towards a target set by alliances, similar governments and the behaviour of neighbours. "Improve relations" raises it at an ongoing cost. A defensive alliance (AllianceAllianceMechanicDefensive alliances bind: if a partner is attacked, all partners join the war on its side. Economic unions only link trade.) pulls all partners into the war when one of them is attacked.
The crisis ladder
Wars usually start as a crisis (Crisis ladderCrisis ladderMechanicConflicts start as a crisis with one demand and escalate in stages: demand, threat/sanctions, mobilisation, ultimatum, war. Every stage costs stability and trade; conceding, a compromise or backing down end it.): a state makes a demand, both sides gather supporters, and the initiator escalates stage by stage – threat with sanctions, mobilisation, ultimatum. Every stage has a deadline of 90 days; the ultimatum runs 30 days. The TensionTensionMap modeCrisis tension of the states (supporters at half). map mode shows where things are heating up.
At every stage there is a way out: the target can concede, either side can offer a compromise, the initiator can back down. Conceding or backing down costs stability; prevailing gains some.
War and peace
If the ultimatum runs out or is rejected, war begins and the demand becomes the war goal. The war is decided by War scoreWar scoreMechanicBalance of a war from −100 to +100 from occupied provinces, battle losses and war exhaustion. It decides which peace terms the enemy has to accept.: occupied provinces, battle losses and War exhaustionWar exhaustionMechanicGrows with the length of wars, losses and occupied provinces and lowers stability. Decays slowly in peace.. A peace offer may only demand what your war score allows; afterwards a truce of 730 days applies.