To date, moral injury remains a syndrome, that is, a group of symptoms lacking clear definition or cause. Phelps exemplifies a possible way ahead in On Killing Remotely. In terms of quantifiability, Phelps makes room for analyzing a new arena for moral injury without stretching the term past its breaking point. In terms of severity, Phelps clarifies that stakes can be high without involving immediate personal danger, thus opening up discussions of comparable scenarios with the potential to morally injure. In terms of technology, Phelps distinguishes between kinds of unmanned or remote aerial technology, sketching a taxonomy and noting the unique stressors of each tool or mission.