If a threat (or threatener) is liable to be defensively killed, there is a defeasible justification for killing her. On certain prevailing assumptions about liability, which I accept, there are liability justifications for killing any number of minimally responsible threats, each of whom would otherwise kill a single non-responsible victim. Absent harms to third parties, these justifications appear, counter-intuitively, to be undefeated. I argue that this counter-intuitive appearance is deceptive.
McMahan (2014). McMahan’s current view that the 20-year-old is not liable diverges from his 2011 view which is that the 20-year-old is liable but the liability justification is overridden (McMahan  p. 154).
McMahan (2009) p. 166.
McMahan (2009) p. 177.
McMahan (2014). McMahan neither rejects nor endorses this claim.