Proportionality and Force in International Law

Proportionality is a fundamental component of the law on the use of force and the law of armed conflict— the jus ad bellum and the jus in bello . In the former, it refers to a belligerent’s response to a grievance and, in the latter, to the balance to be struck between the achievement of a military goal and the cost in terms of lives. The legitimate resort to force under the United Nations system is regarded by most commentators as restricted to...