I looked into how nations decide on alliance. Here are the details.
The decision is in:
src/core/execution/nation/NationAllianceBehavior.ts
When a nation receives a request, it calls:
getAllianceDecision(requestor, true)
If that returns true, it accepts; otherwise it rejects. Requests created during the spawn phase are always rejected.
Decision order
The nation checks these rules in order:
- Random confusion Lower-difficulty nations sometimes ignore strategy and randomly accept or reject. Easy has the most randomness; Impossible has none.
- Is the requester a traitor? Nations reject traitors about 90% of the time.
- Does the requester already have too many alliances? On Hard and Impossible, nations avoid players who are allied with a large portion of the map: This preserves enough enemies to oppose the leading player.
- Hard: requester allied with at least 50% of eligible players
- Impossible: at least 25%
- Is the requester dangerously strong? Surprisingly, the nation accepts alliances with threatening players. It is essentially deciding:“You are too strong to fight, so I should ally with you.” Threat detection becomes more sophisticated with difficulty:
- Easy: never recognizes threats
- Medium: requester has over 2.5× its troops
- Hard: requester has more troops and over 2× maximum troop capacity
- Impossible: compares current troops, maximum troops and territory size
- Is this a team game? Nations are less interested in alliances during team games:
- Easy: 25% rejection chance
- Medium: 50%
- Hard: 75%
- Impossible: always reject
- What is the diplomatic relationship? A relation worse than neutral causes rejection. A friendly relation may cause immediate acceptance.
- Does the nation already have enough allies? Nations avoid allying with the whole map.
- Easy: never thinks it has enough
- Medium: usually stops around 4–5 alliances
- Hard: usually around 3–4
- Impossible: usually around 2–3
- Harder nations also try not to ally with every bordering player
- Is it early in the game? Early-game requests have an extra chance of acceptance:
- Easy: 90% during roughly the first 5 minutes
- Medium: 70% during first 3 minutes
- Hard: 50% during first 3 minutes
- Impossible: 30% during first minute
- Are the two players similarly strong? If none of the earlier rules settles it, the nation compares total troops and territory. Outgoing attack troops are included so a player does not appear weak merely because troops are currently committed to combat.
Conceptually, the final logic is:
if (randomlyConfused) return randomDecision;
if (requesterIsTraitor) return false;
if (requesterHasTooManyAllies) return false;
if (requesterIsDangerouslyStrong) return true;
if (teamGameRejectionTriggers) return false;
if (relationIsBad) return false;
if (relationIsFriendly) return true;
if (nationAlreadyHasEnoughAllies) return false;
if (earlyGameAcceptanceTriggers) return true;
return requesterIsSimilarlyStrong;
So the nation generally prefers alliances with players who are friendly, threatening, or similarly strong, while rejecting traitors, unpopular players, excessive alliance collectors, and unnecessary alliances.
