Wiki

effect · add_to_war

Definition

  • Supported scope:COUNTRY
  • Supported target:none

Description

adds country to the specified war:
ENG = {
	add_to_war = {
	  targeted_alliance = SOV # Country to which side we want to join
	  enemy = PER # Which country we want to declare war on
	  hostility_reason = asked_to_join # The reason for joining the war
	  single_target_only = yes # yes if we want to target only the given country and not all enemies of targeted_alliance
  }
}

Hands-On Notes

Hands-on notes are AI-generated and checked against the vanilla command vocabulary — treat them as a starting point, not authoritative reference. The definition above is the game's own documentation.

Hands-On Usage

add_to_war is commonly used in event-driven diplomatic scenarios, such as when a nation is forced or willingly joins an ongoing war alongside its allies under specific conditions, thereby achieving the narrative effect of "bringing a nation into the conflict." Typical cases include the Soviet Union being forced to declare war on Japan in the historical timeline, smaller nations joining a faction under pressure from major powers, or custom war coalition expansion logic in player mods.

# British event: Soviet Union requests that we join the war against Persia
country_event = {
    id = my_mod.42
    option = {
        name = my_mod.42.a
        # Britain joins the Soviet side and declares war on Persia
        ENG = {
            add_to_war = {
                targeted_alliance = SOV
                enemy = PER
                hostility_reason = asked_to_join
                single_target_only = yes
            }
        }
    }
}

Synergy

  • [has_defensive_war](/wiki/trigger/has_defensive_war) — Validates whether the target party is in a defensive war state before joining, preventing logical contradictions (for example, avoiding situations where you "join the offensive side" while the opponent is shown as the aggressor).
  • [declare_war_on](/wiki/effect/declare_war_on) — When there is no existing war to join and one side must initiate hostilities first, use this command to start the war, then use add_to_war to bring other nations into the conflict. Together they form a complete war declaration workflow.
  • [has_defensive_war_with](/wiki/trigger/has_defensive_war_with) — Confirms that the specified war actually exists and the target nation is already engaged in combat. This is a necessary prerequisite check before invoking add_to_war.
  • [create_wargoal](/wiki/effect/create_wargoal) — After joining a war, supplement your faction with war goals. When paired with add_to_war, this ensures that nations entering the war have clear post-war objectives, rather than simply "fighting without purpose."

Common Pitfalls

  1. The nation targeted by targeted_alliance must already be in the war, otherwise the game will silently error or ignore the command entirely. A common beginner mistake is using add_to_war followed by declare_war_on in the same event, causing execution order to become inverted and the targeted_alliance to remain unengaged when the command fires. Always ensure the allied nation is already at war (using [has_defensive_war_with](/wiki/trigger/has_defensive_war_with) or similar triggers as a gating condition) before executing add_to_war.

  2. Omitting single_target_only will cause unintended chain declarations of war: If left unset or set to no, the joining nation will automatically declare war on all existing enemies of the targeted_alliance, rather than only the single nation specified in the enemy field. This can easily trigger uncontrollable diplomatic chain reactions in multi-front mods.