Proportionate means externalism, in contrast, distinguishes between Gunman and Adversary (Frowe 2014a: 105). On this view, one can be liable to harm that is not the least harmful means of averting a threat, provided that the harm is a means of averting the threat and proportionate to the good secured. Killing Gunman is a means of averting the threat he poses, and is proportionate to saving Victim’s life. Gunman is thus liable to defensive harm on this view. In contrast, since harming Adversary cannot avert the threat she poses, she is not liable to harm.