The increasingly common “preventive” use of military force raises difficult moral and legal issues that seriously challenge prevailing international law. Despite the justifying rhetoric alleging that these anticipatory wars aim to increase or ensure peace and security, such wars pose both moral and political dilemmas. Even when a war is declared in self-defense in response to an actual or imminent show of aggression, it is possible to take a principled pacifist or utilitarian stance instead of resorting to violence. While the long-standing just-war doctrine sanctions military self-defense, and international law endorses it, preventive wars in the name of self-defense when the danger is not actual or imminent raise moral conundrums and lead to problematic outcomes. Also, moral and military hazards of “rescue” wars are compounded when they are preventive wars against anticipated evils. The recent trend of justifying preventive war by blurring the distinction between preemption and prevention with epithets like “gathering threats” does little to clarify the important issues that arise.

The conundrum of whether nations should adhere to existing international law or carry out illegal but morally justified intervention is not new in the context of egregious violation of negative human rights by certain regimes. For instance, illegal intervention in the name of an urgent humanitarian cause occurred in the NATO bombing of Yugoslavia in 1999. But nations hide behind international law in their reluctance to undertake military intervention to enforce basic rights of subsistence. Certainly it is true that raising high barriers to intervention and respecting sovereignty minimizes self-serving military interventions couched in moral rhetoric. If interventions were permitted in inept or failed states in response to their ineptitude, then there would be no limit to military operations, posing a grave threat to the stability of world order. Consequently, “non-interventionism” is the standard thrust of international law, with “reluctant interventionism” being the practice only in exceptional cases.