When Guenther Jakobs introduced the concept of “enemy criminal law” (Feindstrafrecht), or enemy penology, into the legal debate, this was due to a concern with the increasingly anticipatory nature of criminalization in German legislation in the last decades of the 20th century. Against the backdrop of a series of terror attacks in the West and the ensuing debates on how to deal with the dangers and threats of the new millennium, Jakobs’s theory gained new momentum in Germany’s public discourse and beyond. As it seems, the author himself turned the concept into a device for political intervention, declaring the notion of the enemy as indispensable for dealing with certain extreme crimes and notorious offenders, not only to prevent future crime and avert harm from society but also, and most notably, to preserve the established “citizen criminal law” (Bürgerstrafrecht): the enemy is the one to be isolated and excluded from the system. Enemy criminal law may be a peculiar legal concept. The logic of enemy penology, however, leads us to some more fundamental insights into the conundrums of liberal political thinking and attendant legal conceptions. It requires us to think about the enemy as a liminal figure that points to the preconditions and the paradoxes of our legal system. The history of criminology attests to the discipline’s struggle with penal law’s inherent limitations. And if we live today in times where exception and rule, internal security and external security, and military and police concerns increasingly overlap and intermingle in the face of ever new threats, the notion of enemy penology helps us to critically reflect on the mechanisms that drive these transformations.