This chapter examines political and legal conflict over norms of assassination/ targeted killing (A/TK) with a view to assessing the utility of the antipreneur concept proposed in this book. Targeted killing is not defined in international law, but in this chapter I follow a modified version of the definition used by the UN’s Special Rapporteur (2010, 5) on extrajudicial, summary or arbitrary executions: “lethal force . . . deliberately used, with a degree of pre-meditation, against an individual or individuals specifically identified in advance” by a state, when the target is outside a battlefield during armed conflict, does not present an immediate threat to human life, and no judicial authority has approved the action. In most of this chapter, I use the admittedly awkward term A/TK to describe this current practice because, despite becoming increasingly common, it remains controversial. Even its name is disputed, with many opponents using the pejorative term “assassination,” whereas most proponents describe it in more anodyne terms as “targeted killing.” If A/TK is defined as above, then A/TK policies within states hold that it is legal for states to kill in this way, and the evolving international norm of A/TK holds that it is appropriate to do so under certain circumstances. Since the late 1990s, the normative status of A/TK has changed dramatically. From a practice long repudiated by major states as assassination, targeted killing is now a regular practice of some of those same states. These states and likeminded civil society groups provide broad legal justifications for A/TK and vague or secret guidelines for its use. As the Special Rapporteur (2009, 32) has stated, these justifications constitute a “radical departure from past practice.” Nonetheless, other states use or condone the practice and accept the justifications, together creating a new norm of A/TK. Reciprocally, two related prohibitory norms-against assassination and extrajudicial executions (EJE)—have been undermined because the norm of A/TK is unclearly defined and A/TK itself is clandestinely implemented. To be sure, the other norms still exist and receive some support from powerful entities. But the bigger story remains: rapid and profound change toward acceptance of A/TK under a vague and expansive set of norms. What explains this shift in practice and related norms? Does the antipreneur concept contribute to understanding it or normative change more broadly?