 One response is to reject this comparative account of how responsibility determines liability, and argue for a non-comparative approach, according to which one’s degree of responsibility must be great enough to warrant such a severe derogation from one’s fundamental rights. But if we do this, we must surely concede that many combatants on the unjust side are not sufficiently responsible for unjustified threats to be liable to be killed. Whether through fear, disgust, principle or ineptitude, many combatants are wholly ineffective in war, and contribute little or nothing to threats posed by their side. The much-cited research of S. L. A. Marshall claimed that only 15–25 per cent of Allied soldiers in the Second World War who could have fired their weapons did so (Marshall 1978). Most soldiers have a natural aversion to killing, which even intensive psychological training may not overcome (Grossman 1995). Many contribute no more to unjustified threats than do noncombatants. They also lack the “mens rea” that might make liability appropriate in the absence of a significant causal contribution. They are not often blameworthy. The loss of their right to life is not a fitting response to their conduct.