Just War theory - as it was developed by the Catholic theologians of medieval Europe and the jurists of the Renaissance - is a framework for the moral and legal evaluation of armed conflicts. To this day, Just War theory informs the judgments of ethicists, government officials, international lawyers, religious scholars, news coverage, and perhaps most importantly, the public as a whole. The influence of Just War theory is as vast as it is subtle - we have been socialized into evaluating wars largely according to the principles of this medieval theory, which, according to the eminent...