Over the past decade, U.S. officials have taken steps to institutionalize the practice of targeted killing of persons outside an identifiable war zone. In the past, such a policy would have been described as extra-judicial killings. Advocates of this policy claim that the practice is permissible because the executive reviews and authorizes every targeted strike. I examine the tenability of this claim in light of Aquinas’s understanding of the natural principles of justice and their implication for our definition of murder (...) and the duties of a sovereign judge to those subject to his judgment. I conclude that Aquinas’s understanding of murder is expansive enough to include the use of lethal force by public authorities when it proceeds from an act of judgment that disregards a presumption of innocence for the accused and her right to a fair trial. (shrink)