Justification for War

In traditional just war theory, a distinction is drawn between principles relating to the justification for waging war—jus ad bellum—and principles relating to moral conduct during war—jus in bello. More recently, it has been argued that such an analysis is incomplete and a third element concerning post-war conduct—jus post bellum—has been proposed. This chapter examines the social contract theories of Hobbes, Locke, Rousseau and Kant in relation to the first of these. We will see that, although the theorists share many fundamental beliefs, their theories can lead to very different conclusions in this respect. In order to fully understand their views an analysis of the concepts of war and peace will first be examined.