The Laws of War and the 'Lesser Evil'

Harvard Law School Faculty Scholarship Series Working Paper No. 24

Yale Journal of International Law, Vol. 35, No. 1, 2010

69 Pages Posted: 14 Dec 2008 Last revised: 24 Dec 2009

Date Written: December 12, 2008


One of the fundamental principles of international humanitarian law (IHL) is that it recognizes no lesser-evil justification for breaking its rules. Those violating the laws of war will thus be viewed as war criminals even when their conduct was intended to - and in fact did - prevent much greater harm. This Article argues that this deep-rooted absolutist stance undermines the humanitarian drive of the laws of war, and offers, instead, a lesser-evil defense.

The argument begins with the obvious analogy to the necessity defense in domestic criminal law, emphasizing the adaptations that are necessary in order to transpose the domestic concept onto the international plane. It then proceeds to test possible first-order accounts – deontological, consequentialist, and institutional – for why IHL might nonetheless prefer a more absolutist stance than domestic law. It finds that none of these accounts offers a compelling explanation for the exclusion of any lesser-evil justification from IHL.

The Article then proceeds to develop a blueprint for the concept of a humanitarian necessity justification that would exculpate an actor who violated the laws of war in the name of a greater humanitarian good under certain conditions. A central component of the justification, which is required given the special nature of IHL, is a condition that the greater humanitarian good would benefit the enemy, rather than the actor’s own people.

Keywords: international law, laws of war, international humanitarian law, necessity, double effect, civilians, torture, Hiroshima, early warning procedure

Suggested Citation

Blum, Gabriella, The Laws of War and the 'Lesser Evil' (December 12, 2008). Harvard Law School Faculty Scholarship Series Working Paper No. 24; Yale Journal of International Law, Vol. 35, No. 1, 2010. Available at SSRN: or

Gabriella Blum (Contact Author)

Harvard Law School ( email )

1575 Massachusetts
Hauser 406
Cambridge, MA 02138
United States

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