Overview

Just War Theory is the attempt to restrain the horror of war with morality. It asks: “When is it right to fight?” and “How should we fight?”

Core Idea

The core idea is Justice. War is terrible, but sometimes it is the lesser of two evils.

Formal Definition

  • Jus ad Bellum (Justice of War): When is it right to start a war? (Self-defense, Last Resort, Right Intention).
  • Jus in Bello (Justice in War): How must you behave? (Proportionality, Discrimination between civilians and soldiers).

Intuition

  • The Policeman: A policeman can use force, but only to stop a crime, and only as much as necessary. Just War views the soldier as a global policeman.
  • The Shield: You fight to protect the innocent, not to conquer.

Examples

  • WWII: Generally considered a Just War (stopping Nazi aggression).
  • Vietnam/Iraq: Highly debated. Was there a just cause? Was it a last resort?

Common Misconceptions

  • Misconception: “All’s fair in love and war.”
    • Correction: That is Realism. Just War says there are rules (Geneva Conventions).
  • Misconception: It’s pacifism.
    • Correction: Pacifism says war is never right. Just War says it can be right.

Applications

  • Rules of Engagement (ROE): Soldiers are trained on when they can shoot.
  • War Crimes Tribunals: Punishing those who break the rules.

Criticism and Limitations

  • Subjectivity: Every side thinks their war is just.
  • Modern War: How do you distinguish civilians in a guerrilla war?

Further Reading

  • Just and Unjust Wars by Michael Walzer