The rules of war apply equally to the aggressor and resister, regardless of the justice of the cause: Soldiers have moral equality on the battlefield and that “distinguishes combat from domestic crime” (128). To ensure this, the rules of war must be defined. Henry Sidgwick argues for a twofold rule, which means that there shall be no mischief unrelated to victory or military necessity and that said mischief must be proportional to its contribution to victory. Walzer criticizes this utilitarian approach for valuing victory over the interests of human beings. While Sidgwick’s rule does offer some restrictions on soldiers’ actions, it does not identify rules that a soldier cannot violate for the sake of military necessity. To remedy this, Walzer turns to rights theory to identify such rules.

Invoking the rape of Italian women in 1943 by Moroccan soldiers, Walzer explains that rape is a crime because it violates women’s rights. It was wrong to give the mercenary soldiers license to rape Italian women because legitimate acts of war cannot violate the rights of noncombatants. Therefore, domestic crimes such as murder and rape are banned.