War may well be another means of politics, as Carl von Clausewitz famously observed. But like Machiavelli, who had similar thoughts, Clausewitz is not an appealing character in the history of political philosophy. His views on the primacy of the national interest over ethics have remained as controversial now as they were when he first set pen to paper. Indeed, some may regard the firm denial of war as just another option of policy, a denial now enshrined in the Charter of the United Nations, as the principal achievement of civilisation since that time.
Self-defence applies
Of course, a defensive war remains legitimate, provided the strict conditions of self-defence enunciated in Art 51 of the UN Charter are met. Since 9/11, it is clear that self-defence can also be invoked against non-state actors, in that case the
