The purpose of this chapter is to trace the history and content of the U.S. Catholic bishops' position on Selective Conscientious Objection (SCO). The paper will proceed in three steps: (1) an interpretation of the development and logic of Catholic moral teaching on warfare; (2) an exposition of the specific statements on SCO made by the bishops; and (3) a commentary on the questions which flow from the tradition and the position of SCO.