I construct a genealogy of the principle of distinction; the injunction to distinguish between combatants and civilians at all times during war. I outline the influence of a series of discourses--gender, innocence, and civilization --on these two categories. I focus on the emergence of the distinction in the seventeenth-century text "On the Law of War and Peace", authored by Hugo Grotius, and trace it through the twentieth-century treaties of the laws of war--the 1949 Geneva Protocols and the 1977 Protocols Additional. (...) I draw out how the practices of and referents for our current wars partially descend from and are governed by the binary logics of Christianity, barbarism, innocence, guilt, and sex difference articulated in Grotius's text. These binaries are implicated in our contemporary distinction of "combatant" and " civilian," troubling any facile notion of what "humanitarian" law is or what "humanitarian" law does, and posing distinct challenges to theorizations of the laws said to regulate war. (shrink)