The United States has a self-interested desire to wage post- heroic war, and it has a moral duty to do so justly. To the extent that the world is an orderly society governed by rules, a concern for justice can and should act as a restraint on states’ pursuit of self- interest, especially when the means of pursuit is violence. The history of war has frequently demonstrated, however, that the relationship between self- interest and justice is one mediated by technology and technological advantage. Where technology lowers one side's expectations of loss resulting from the use of force, the pursuit of self- interest is made easier and the temptation to use force unjustly can increase. In particular, the combination of technologies underpinning airpower and long-range communication, by moving the practice of war far beyond its hand-to-hand combat origins, has made it easier for some states to apply force from a great distance. In the case of America's use of armed drones, remote-controlled killing is carried out in a way that is also largely unseen by would-be targets, unintended victims, US citizens and outside observers alike. Such invisibility can enable the surmounting of erstwhile obstacles to the achievement of self- interest, and justice too could thereby well be served. Alternatively, the increased power afforded by invisibility could generate a powerful temptation to act without regard to what other actors might think is unjust. In Plato's The Republic, Glaucon observes that a system of morality is a compromise between people's ‘natural’ pursuit of their own interests ‘regardless of others’ and the need to ‘run an orderly society’. He then argues that, if the sanctions of that system are removed, it would profit a person more to act unjustly.1 Glaucon illustrates the power of unrestrained liberty to pursue self- interest by recounting the tale of a shepherd, named Gyges, employed by the king of Lydia. One day, after an earthquake, Gyges discovered a gold ring in a chasm in the earth. He wore the ring at a meeting of shepherds who reported monthly to the king on the state of his flocks. When Gyges happened to twist the ring on his finger, ‘he became invisible to his companions’, and he became visible again when he twisted the ring in the other direction. Soon afterwards, empowered by the ring to act unseen, he was able to enter the king's palace, seduce the queen, murder the king and seize the throne of Lydia for himself.2 With such a magic ring, Glaucon suggested, a man could ‘generally behave as if he had supernatural powers’, and 113acting unjustly (seducing, murdering and stealing) would pay better than acting justly.3