Full Idea
When one cannot count on the moral code of the oppressor, nonviolence is either a disguised form of surrender or a minimalist way of upholding communal values after a military defeat.
Gist of Idea
If the oppressor is cruel, nonviolence is either surrender, or a mere gesture
Source
Michael Walzer (Just and Unjust Wars [1977], Afterword)
Book Reference
Walzer,Michael: 'Just and Unjust Wars' [Penguin 1984], p.333
A Reaction
The point is that ruthless conquerors may just kill the nonviolent, so it would achieve nothing. Nonviolence is only a plausible strategy in a fairly civilised world. Hard to disagree.