War has an obvious impact on human well-being, one that is almost always deleterious. Whatever good a given war might conceivably produce or whatever evils it may forestall, by definition it involves death and destruction, mayhem and misery. Even in periods of peace, the need to be prepared for war also affects human well-being, diverting human and material resources along channels that, viewed by themselves, are less productive of well-being than obvious alternatives to them. It is not surprising, then, that Jeremy Bentham and James Mill were concerned with the causes of war and how best to avoid it. However, neither they nor John Stuart Mill, who wrote about some of the violent conflicts of his day, addressed in sufficient detail two key ethical questions: (1) when, if ever, are we morally justified in waging war and (2) if recourse to arms is warranted, how are we permitted to fight the wars we wage? Nor have contemporary utilitarians examined these questions with the care they deserve. After reviewing briefly what Bentham and the Mills had to say about war, this essay addresses these two questions from a utilitarian perspective.

Bentham and the Two Mills

Bentham disapproved of war and sought its elimination. “All war is in its essence ruinous,” he wrote; “mischief upon the largest scale.” An anachronism in the modern world, war damages the interests of the masses, forcing them “to murder one another for the gratification of the avarice or pride of the few.” The few, in turn, rarely suffer the miseries brought about by the wars they direct. Bentham firmly rejected the idea that war benefits the national economy. It leads, rather, to higher taxation and increased executive power, and the colonies and trading privileges that are sometimes won by war do little or nothing to increase a nation’s wealth. On the other hand, he believed that the frequency of war could be reduced by free trade, the development of international law, a foreign policy that was open to scrutiny and based upon non-interference with other nations, and by an effort to combat popular enthusiasm for war by debunking concepts like national honor and martial glory.