Militarism glorifies war. Pacifism condemns it absolutely. Just War Theory treats war as an evil, but one that is sometimes necessary and morally defensible. So when is a state justified in resorting to military force? Traditionally, Just War theorists have maintained that only national self-defence against aggression constitutes a just cause. More recently this view has come under critical pressure. Some contemporary Just War thinkers see the traditional view as too permissive insofar as it licences the use of force – and the death and destruction attendant thereupon – in response to any breach of political sovereignty or territorial integrity. Others see the traditional paradigm as too restrictive insofar as it forbids both armed humanitarian intervention (the use of force to defend foreign nationals against a murderous or oppressive government), and preventive action to neutralise a threat in advance of its materialization (to eliminate WMDs, for instance). This course will provide students with a comprehensive overview of the philosophical debate over when the use of military force is morally justified.