This thoughtful passage from the Preamble of the UN Charter evokes ideas essential to a cosmopolitan ethics of armed conflict. What are the moral principles that should be accepted, in order to ensure that armed force is used only in the common interest? So as to protect civilians, what moral methods governing the use of armed force should be instituted? Should the term ‘armed force’ encompass all forms of armed conflict? What is the common interest worldwide? Should such questions be answered by means of a just war theory? These questions are somewhat vague, but they serve to indicate the sorts of questions that I am striving to answer in this book.

I. PREVIEW

Following some introductory remarks in the first and second parts of this chapter, the third part cites four epochal events that have been pivotal for just war theory – namely, the framing of the UN Charter and the founding of the United Nations, the Cold War practice of military deterrence, the post-Cold War recognition of the responsibility to protect and the advent of the current global war on terror. The fourth part contains some concluding remarks.