Killing in War and the Moral Equality Thesis

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In his famous book Just and Unjust Wars, Michael Walzer articulates a thesis he calls the “Moral Equality of Soldiers,” namely, the principle that combatants have an equal right to kill other combatants in war, regardless of the justice of the cause for which they are fighting. The Moral Equality Thesis, as I shall call it, is an essential component of traditional Just War Theory, in that it provides the basis for distinguishing the jus in bello from the jus ad bellum. It also plays a crucial role in identifying the nature of the difference between combatants and civilians. The Moral Equality Thesis has recently come under attack by scholars of Just War Theory, notably philosopher Jeff McMahan, on the grounds that killing for immoral purposes cannot be justified, and so it cannot be true that combatants all have an equal right to kill, regardless of the justice of their cause. In this essay, I defend the Moral Equality Thesis in its traditional formulation. Without it, I argue, the rule of law would not apply in war. The failure to recognize the equal right of combatants to kill in war, I suggest, creates an inconsistency between the rules of war and basic concepts in the law and morality of self-defense, an inconsistency that McMahan himself would think undesirable. I argue that McMahan’s argument applies more compellingly to armed conflict in asymmetrical warfare. Arguably, the Moral Equality Thesis does not apply in an armed conflict between combatants and unlawful combatants. In that context, the divergence from the law and morality of self-defense is less of a concern.

Publication Title

Social Philosophy & Policy

Publication Citation

32 Soc. Phil. & Pol'y 184 (2016)

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