This chapter begins by explaining how PAM was supposed to work and how public expressions of moral repugnance led to the project being shut down. It introduces and explains the psychology of moral repugnance and discusses a taxonomy of kinds of moral repugnance that might result from the rollout of a new or disruptive technology for security purposes. Garden-variety, or regular, repugnance is best thought of as intense revulsion – finding something extremely disgusting. Since moral intuitions can be biased, and therefore unhelpful, policy makers should use widespread moral repugnance as a red flag – a warning that a thorough moral investigation may be warranted. The best way to respond to moral repugnance depends very much on whether or how the repugnance is, or could be, justified. The first step is to assess any apparent moral repugnance. Combining in-house brainstorming and primary and secondary research, gather all of the instances of potential moral repugnance.