Full Idea
The purpose of reprisals is not to win the war or prevent defeat, but simply to enforce the rules [of war].
Gist of Idea
The aim of reprisals is to enforce the rules of war
Source
Michael Walzer (Just and Unjust Wars [1977], 13)
Book Reference
Walzer,Michael: 'Just and Unjust Wars' [Penguin 1984], p.212
A Reaction
That may be wishful thinking, since reprisals are often vastly more ruthless than the original offence, and there is often injustice in the nature of the reprisals, since they cannot be precise.