There can be no self-defence without proportionality, because, if excesses are committed in the context of defensive action, then the use of force ceases to be legitimate and becomes aggression dissociated from any prior occurrence.
自卫不能脱离适度原则，因为，如果自卫行动超出限度，那么使用武力就不再是合法的，而会成为同任何先前发生的事件无关的侵略。