This is the second chapter of two on military human enhancement. In the first chapter, the authors outlined past and present efforts aimed at enhancing the minds and bodies of our warfighters with the broader goal of creating the “super soldiers” of tomorrow, all before exploring a number of distinctions—natural vs. artificial, external vs. internal, enhancement vs. therapy, enhancement vs. disenhancement, and enhancement vs. engineering—that are critical to the definition of military human enhancement and understanding the problems it poses. The chapter then advanced a working definition of enhancement as efforts that aim to “improve performance, appearance, or capability besides what is necessary to achieve, sustain, or restore health.” It then discussed a number of variables that must be taken into consideration when applying this definition in a military context. In this second chapter, drawing on that definition and some of the controversies already mentioned, the authors set out the relevant ethical, legal, and operational challenges posed by military enhancement. They begin by considering some of the implications for international humanitarian law and then shift to US domestic law. Following that, the authors examine military human enhancement from a virtue ethics approach, and finally outline some potential consequences for military operations more generally.