The genesis of this book lies in a March 2005 symposium on the ‘Just War in the Twenty-First Century’ and the context for the encounter was the 2003 Iraq War, a conflict that helped to crystallise in the most acute way the recurring moral, political, legal and military tensions that are involved in the recourse to and conduct of war. Historically, the framework used most frequently to explore these issues has been the just war tradition and the symposium aimed to facilitate a transatlantic dialogue involving a diverse range of participants on the ethics of war and peace with a view to investigating and renewing that tradition as part of a broader public conversation.

The starting point of the symposium, as well as of this book, is the premise that the just war tradition remains an indispensable framework for analysing global order, peace and security. In our view, it is critical to see just war thinking as a dynamic tradition for reflecting on the nature of international society rather than as a set of prescriptions to be rigidly applied to crises, a sort of checklist that can be ticked or crossed. Even more fundamental to the volume is the belief that conflict tragically remains an inextricable part of both intra- and inter-state relations. Therefore, trying to understand such a fundamental phenomenon is itself a moral obligation and the just war remains the best way to do so.