This chapter introduces the research question around which the book is organized: how do we explain why human societies create rules for protecting civilians in war? It then introduces the main argument of the book, which is that universal moral beliefs and emotions influence the development of civilian protection norms. Finally, it provides an overview of the book and a brief review of each of the chapters.

The concluding chapter summarizes the theoretical analysis and empricial findings of the preceding chapters. It then argues that one of the key problems with the laws of war is that they enable states to evade accountaibility for imposing high risks on the civilian population. Although the principles of distinction and proportionality impose some restraints on what states can do in war, the permissive effects of the principle of proportionality provide states with significant flexibility when it comes to battlefield decisions that threaten civilians. Building on Jurgen Habermas's discourse ethics, it argues for a principle of affected interests that would correct for some of the permissive effects of the laws of war by requiring states to give equal consideration to civilians in how the incidental risks of war are distributed.