This article argues against the argument that justifies violence when it is used to protect of a third, innocent party. My confutation presents various counter-arguments. It shows that the effectiveness of this extreme case is based on an extreme coercion: the threat of death. But such a coercion has the same heuristic power of a tautology, from which anything follows: correct and incorrect conclusions. Moreover, the argument treats violence and non-violence as contrary categories, and not as different ones. It allows an erroneous inference, inasmuch as it assumes that from the confutation of the one, the other follows.