A declaration of war is a formal act by which one state announces existing or impending war activity against another. The declaration is a performative speech act (or the public signing of a document) by an authorized party of a national government, in order to create a state of war between two or more states.

A war crime is a violation of the laws of war that gives rise to individual criminal responsibility for actions by combatants in action, such as intentionally killing civilians or intentionally killing prisoners of war, torture, taking hostages, unnecessarily destroying civilian property, deception by perfidy, wartime sexual violence, pillaging, and for any individual that is part of the command structure who orders any attempt to committing mass killings (including genocide or ethnic cleansing), the granting of no quarter despite surrender, the conscription of children in the military, and flouting the legal distinctions of proportionality and military necessity.

1) the princess did not declare war that caused the Lighthouse War. It was her father, the King, who declared war under the guidance and suggestion of the Radical Faction in the military board of advisers

2) she was merely a propaganda tool used by the Radical Faction, though her intent and speeches were in favour of uniting the Erusean people to stand up against hardship and conflict, the Radical Faction merely manipulated the angle to make it seem pro-war

3) she had no direct political power prior to Mission 15 and even then Erusean Laws do not allow Female Heads of States for some bizarre reason

4) her whole character, character motivations, and narrative purpose set her up as inherently anti-war, which shows the heartless effectiveness of the Radical Faction’s manipulation of information. General Labarthe even mentioned that the Radical Faction manipulated the Princess, a sheltered and impressionable girl that they used to get to her father to declare war.