Just and Unjust Wars: A Moral Argument With Historical Illustrations

In Just and Unjust Wars: A Moral Argument with Historical Illustrations, Michael Walzer presents a theory about when war is and is not morally defensible. He expounds upon the legitimate means to fight in a war, holding all soldiers to the same standards. A professor of government at the time of publication, Walzer’s work sparked an increase in academic literature focused on just war theory, political philosophy, and international relations. Originally published in 1977, the book has gone through five editions and is now considered a classic in the field.

All quotations and references in this guide are from the fifth paperback edition published in 2015.

Plot Summary

Assuming a common sense of morality grounded in a belief in human rights, Walzer challenges the realist paradigm of waging war. That paradigm places no restrictions on war and bases foreign policy decisions on interests, not values. Instead, Walzer argues that war is morally evaluated in two distinct ways, namely jus ad bellum or justice of war and jus in bello or justice in war. The two are separable, as it is possible for a just war to be fought unjustly and for those on the unjust side to fight justly.

Addressing the justice of war first, Walzer explains that the initiation of war is an act of aggression and therefore criminal. Such a violation of a state’s territorial integrity and political sovereignty justifies a military response from the victim and other states. Walzer additionally considers a state justified in responding militarily to a sufficient, not necessarily imminent, threat of force. In addition to self-defense, Walzer permits military intervention in three cases: large-scale military struggles for secession or national liberation, a war in which another foreign power has already intervened, and cases of extreme violations of human rights. In such cases, the onus is on the intervening party to justify its involvement. Walzer sets a high bar in cases of humanitarian intervention, requiring massacres, enslavement, or similar violations: Wars are limited and should not become crusades. Walzer calls upon adversaries to make peace when goals have been reached, arguing that it is not typically necessary to replace the regime of a country. Acknowledging that unconditional surrender and regime change were indeed necessary in the case of Nazi Germany, Walzer maintains that the war with Japan could have ended with conditions and without the use of nuclear weapons in 1945.

Walzer seeks to strengthen the war convention, which morally governs the rules of war or jus in bello. He is critical of a purely utilitarian approach, which justifies the killing of civilians if it is militarily necessary. Walzer distinguishes between combatants and noncombatants and provides the latter with immunity. He proposes a revision of the standard of double effect, which allows civilians to be killed in a legitimate act of war if the direct effect is morally acceptable—such as bombing a military installation—the actor’s intentions are good, and the good effect is proportional or sufficient to compensate for the evil done. Instead, Walzer calls for a double intention whereby the actor must not only intend good but act to reduce the evil as much as possible even at risk to self. Consistent with his goal of protecting the rights of noncombatants, Walzer condemns siege warfare, unless civilians are provided safe passage, and terrorism for targeting innocent people. He also deems reprisals that target civilians unjust. Guerrilla warfare challenges Walzer’s distinction between combatants and noncombatants, as the guerrillas mix with the general population and do not wear uniforms. Walzer labels guerrillas who do not have popular support criminals but allows the rights of guerrillas to grow as popular support does. With sufficient popular support, they become one with the populace and it is then wrong to wage war against them. He argues that this was the case in Vietnam.

Acknowledging the possibility of a conflict between jus ad bellum and jus in bello, Walzer allows for the rules of war to be broken in the case of a supreme emergency. Ordinarily, those fighting on the side of justice do not have more leeway to break the rules than the aggressors. He limits supreme emergencies to times of both an imminent danger and catastrophic threat. For example, the Nazis posed a catastrophic threat to the democratic world, but the rules of war had to be followed in all cases unless doing so would have allowed for their imminent victory. Indeed, he criticizes England for breaking the rules of war with its bombing of German population centers late in the World War II. Similarly, Walzer demands that belligerents in a war respect the rights of neutral countries unless national or civilizational survival is at stake. Walzer condemns nuclear war and the threat of nuclear war, on which deterrence theory depends. Since he does not provide an alternative means to maintain peace in a world with nuclear weapons, he allows deterrence as a form of permanent emergency.

Walzer holds political leaders and supporters accountable for starting unjust wars. He believes it is possible and appropriate to assess collective responsibility, especially in a democracy. However, he acknowledges the complexity of so doing, given the imperfect nature of democracies. Both soldiers and officers must be held accountable for crimes in war, though officers have a higher level of responsibility. There are instances when soldiers are coerced to commit crimes, such as when they are in fear of their life. In such cases, they are not morally accountable. However, they are responsible in the absence of such a direct threat. Walzer closes with consideration of non-violent resistance to an aggressor. Such a form of resistance transforms the struggle from a military to political one. The success of such resistance is entirely dependent upon the aggressors obeying the war convention and therefore not killing peaceful resisters. He reiterates the essential need for all soldiers to heed the war convention in his postscript. Without it, there is no possibility of a transformation to non-violent conflict and no limitations in war. Both sides will claim the mantle of justice.