In recent years, conventional just war thinking has been subjected to powerful scrutiny. Revisionist critics, animated by a commitment to individual human rights, and scepticism about the moral importance of states, have undermined the arguments grounding doctrines as widely accepted asstates' rights of national defence, the principle of noncombatant immunity, and combatants' equal right to fight. They have argued, in particular, that our ordinary understanding of national defence cannot be justified on individualist grounds - and that there is no alternative to an individualistjustification. But while their challenges to the conventional view have been powerful, their alternatives have been less compelling. Some positive account of the morality of defensive war is required, along one of three lines: Either we must concede that wars of national defence are unjustified, and adopt a restricted form of pacifism (with a possible exception for averting mass atrocity crimes); alternatively, either theindividualists must explain how their theory is consistent with our strongly-held judgments about national defence, or advocates of the conventional view must provide compelling alternative theoretical justifications for their position. In their original contributions to The Morality of DefensiveWar, the leading advocates of the revisionist and conventional approaches to the morality of war develop each possibility in detail. Part I sets out, in new and more forceful terms, the challenge that our ordinary views about national defence represent. In Part II individualists response to thatchallenge. Part III develops new approaches to vindicating the conventional view.