Full Idea
Objections to combatant equality appeal to a sliding scale of 'the more justice, the more right'. …It allows the justice of one's cause to make a difference in the way one fights. …The extreme says soldiers fightly justly can do anything that is useful.
Gist of Idea
Rejecting Combatant Equality allows just soldiers to be harsher, even to the extreme
Source
Michael Walzer (Just and Unjust Wars [1977], 14)
Book Reference
Walzer,Michael: 'Just and Unjust Wars' [Penguin 1984], p.229
A Reaction
This slippery slope fear seems to be Walzer's main argument in favour of the moral equality of combatants. See Jeff McMahan for the opposing view.