When is war justified? What conduct is permissible on the battlefield? Questions like these have troubled political thinkers for as long as people have waged war. Augustine of Hippo provided an early examination of the conditions for just warfare, suggesting that defense of oneself, or others in need, was not only a moral justification for warfare, but an imperative. Later, in his Summa Theologica, Thomas Aquinas put forward the basis of modern just war theory, suggesting that war cannot be fought for personal gain and must be waged by a legitimate body, and that the overriding motive must be to secure peace.

However, recent rapid advances in military industrialization, complex interrelations between states, and the emergence of guerrilla warfare all challenge the solidity of the ethical underpinning to armed conflict. Michael Walzer is a US political philosopher regarded as one of the most eminent just war theorists of the last century. His work has reinvigorated just war theory and provided the impetus for a new set of responses to the complexities of conflict. For Walzer, war is, in certain circumstances, necessary, but the conditions for warfare and its conduct are subject to strong moral constraints and ethics.

  However, Walzer believes that a just and necessary war may need to be fought to the full extent of the means available, however horrific that might seem. For instance, if the killing of civilians is judged likely to hasten the end of the war, it might be justified. He believes that those waging war should be subject to moral restraints, but that those restraints cannot be absolute.

Just and unjust wars

Walzer’s Just and Unjust Wars argues for the maintenance of a strong ethical base, while holding that warfare is sometimes necessary, but rejects moral absolutism—the idea that some acts are never morally permissible.

  Walzer suggests that in modern conflicts, the muddied dynamics of the battlefield and the complex ethics involved provide challenges to ethical thinking. He gives the Allied bombing of Dresden in World War II as an example of a very difficult case to judge. Nuclear weapons, in particular, trouble Walzer, who suggests that they shift the boundaries of morality so drastically that it is now difficult to make a moral framework for warfare. However, as a last resort, even the most extreme measures might be justified.

The use of nuclear weapons in war profoundly affected Walzer’s ideas. The immense destructive capabilities of these weapons led him to urge a reassessment of the ethics of warfare.

MICHAEL WALZER

Michael Walzer was born in New York and attended Brandeis University, Boston and the University of Cambridge in the UK before completing his doctorate at Harvard in 1961. He went on to teach a course at Harvard in the 1970s in tandem with Robert Nozick, which provided the genesis for two influential books: Nozick’s Anarchy, State, and Utopia, and Walzer’s Spheres of Justice. He was made emeritus professor at the Institute of Advanced Study at Princeton University in 2007.

  Walzer’s work has been influential in a number of areas, including just war theory, but also taking in equality, liberalism, and justice. As a supporter of self-governing communities, he has been concerned with civil society and the role of the welfare state. A leading public intellectual, his work on just warfare has influenced many contemporary politicians and military leaders.

Key works

1977 Just and Unjust Wars

1983 Spheres of Justice

2001 War and Justice