Full Idea
For consequentialists there will be nothing that it will not be right to do to a perfectly innocent individual, if that is the only way of preventing another agent from doing more things of the same kind.
Gist of Idea
Consequentialists can hurt the innocent in order to prevent further wickedness
Source
Philippa Foot (Utilitarianism and the Virtues [1985], p.61)
Book Reference
Foot,Philippa: 'Moral Dilemmas' [OUP 2002], p.61
A Reaction
This is her generalised version that Williams dramatised as Jim and the Indians. Roughly, if you achieve a good outcome, it matters little how it is achieved. Foot sees consequentialism as the main problem with utilitarianism.