The set of core just war principles contains a proportionality principle, but not a legitimate authority principle. In this chapter, the ideas of proportionality and authority are elucidated by means of comprehensive moral principles of distributive justice and autonomy.

I. PROPORTIONALITY

Presumably, in this quotation, the term ‘incidental’ adumbrates the legal requirement that such harmful effects must not be intended, and the term ‘excessive’ adumbrates a legal standard of proportionality. In addition to mandating that civilians ‘shall not be the object of attack’ (ICRC 1977a: Article 51(2)), Protocol I mandates that civilians must be spared from unintended but disproportionate harm. In Protocol I, the idea of noncombatant immunity is interrelated with the idea of proportionality.

But the two ideas are different. Instead of complicating the noncombatant immunity principle formulated in the preceding chapter by incorporating a qualification concerning proportionality, my view is that a proportionality principle should be formulated separately. A purpose of this first part of the present chapter is to propose and support a generalised just war principle of proportionality that is applicable by all sorts of responsible agents to all forms of armed conflict.