Book summary “Just and Unjust Wars”: summary

Introduction

You face a profound moral dilemma when state coercion and mass violence clash with individual human rights. Modern warfare threatens total destruction while demanding strict adherence to ethical limits. You need a reliable framework to judge when fighting is justified and how combatants must behave.

The central idea of the book is that war is a moral reality structured by two distinct frameworks. You must separate jus ad bellum, the justice of war, from jus in bello, justice in war.

The book guides you through this complex landscape by examining specific problems.

• When does state aggression justify armed resistance?
• How do you protect noncombatants during total conflict?
• What happens to moral rules during supreme emergencies?
• Who bears ultimate responsibility for wartime actions?

1. The Moral Reality of War

Against Realism

Realism claims that war is a realm of necessity and self-interest where laws and morality are silent. Defenders of this view argue that war strips away civilization to reveal a fearful human nature under pressure. This perspective treats moral talk about war as idle chatter or a mask for raw power struggles.

War is not a lawless realm of pure realism; it is shaped by a persistent moral vocabulary and shared human judgments.

Thucydides' Melian dialogue is the classic literary expression of realism, where Athenian generals reject justice for brute power. At Melos, Athenian generals Cleomedes and Tisias told the magistrates that the strong exact what they can and the weak yield. They asserted that empire expansion is driven by a natural necessity of inter-state politics to reign or be subject.

In the winter of 416 B.C., after Melos refused to surrender and Spartans sent no help, Athenians slew all men of military age, enslaved women and children, and planted a colony of 500 men.

The Crime of War

The moral reality of war is fixed by the opinions and shared judgments of mankind. Agony and moral difficulty in war are products of shared human moral views. Observers and participants hold people responsible because they view them as participants rather than mere victims.

The existence of hypocrisy in wartime discourse is clear evidence of the stability and persistence of human moral values. Leaders lie and use hypocrisy to justify themselves because they know their actions will be judged against shared moral standards. Hypocrisy is the tribute incompetence or immorality pays to understanding.

Harry Truman asserted he never lost sleep over dropping the atomic bomb on Hiroshima, whereas political leaders typically find it preferable to stress the painfulness of decision-making as a burden of office.

The moral reality of war is divided into two logically independent judgments regarding reasons for fighting and means adopted. Medieval writers distinguished jus ad bellum, which involves judgments about aggression and self-defense, from jus in bello, which concerns rules of engagement. Because these judgments are logically independent, a just war can be fought unjustly, and an unjust war can be fought strictly according to the rules.

Modern war becomes a form of tyranny and hell when states use conscription to force impoverished or unwilling men into battle. Unlike consensual combat, modern warfare relies on state coercion and mass mobilization, making soldiers cheap and turning battles into slaughter. Because combatants are compelled by the state as political instruments rather than acting of their own free will, war loses its appeal and becomes an object of moral condemnation.

Napoleon boasted to Metternich that he could afford to lose thirty thousand men a month, a scale of loss possible only through state coercion.

The Rules of War

Despite fighting in criminal wars, ordinary soldiers are recognized as moral equals who share a common servitude. While a war may be launched by criminal aggressors, soldiers forced to fight on opposing sides recognize each other not as personal enemies, but as victims trapped in a war they did not make. This shared servitude provides the basis for the rules of war, allowing soldiers to kill each other in combat while prohibiting atrocities against the wounded or those surrendering.

On Christmas Day 1914, German and French troops briefly came together in no-man's land to drink and sing, illustrating the underlying recognition of moral equality.

The rules of war consist of two distinct clusters of prohibitions governing how soldiers can kill and whom they can kill. The first set of rules dictates how and when combat occurs, such as weapons used or tactical methods, which are circumstantial and culturally variable. The second set of rules restricts whom can be attacked, insulating noncombatants, the wounded, and those who surrender by connecting immunity to military disengagement.

Ancient Indian texts specified that observers, grieving individuals, sleeping or thirsty persons, and those with unfinished tasks should not be subjected to battle.

2. The Theory of Aggression

Aggression is the supreme international crime, violating the territorial integrity and political sovereignty of independent states.

Every violation of a state's territorial integrity or political sovereignty is labeled aggression because aggressive acts force people to risk their lives to defend their rights. Unlike domestic property crimes where the victim's surrender reduces guilt, aggression remains a singular crime because it threatens rights worth dying for, and unresisted aggression remains aggression still. The German seizures of Czechoslovakia in 1939 through extortion without combat versus the armed resistance of Poland illustrate this dynamic.

The rights of states to territorial integrity and political sovereignty derive ultimately from the individual rights of their members and their shared common life. States are collections of individuals bound by a social contract process that creates a common life over time. Territorial integrity and political sovereignty are functional protections of this shared existence rather than mere property ownership of vast lands.

The dispute over Alsace-Lorraine in 1870, where the legitimacy of sovereignty depended on the political allegiance of local inhabitants rather than ancient dynastic titles, demonstrates this principle.

The legalist paradigm structures international morality through six core propositions modeled after domestic law and order:

• international society consists of independent states;
• international law sets a boundary between them;
• any use of force by one state against the territorial integrity or political sovereignty of another constitutes aggression;
• aggression justifies two kinds of violent response: self-defense and law enforcement;
• nothing but aggression can justify war;
• the aggressor state can be punished.

Law and Order in International Society

You can understand the legalist paradigm as an international equivalent of domestic assault or murder. Aggression is the sole crime that independent states can commit against other states.

Anticipations and Pre-emption

Legitimate first strikes are justified not by imminent attack or mere preventive fear, but by the presence of a sufficient threat. Boastful ranting, classic arms race military preparations, hostile acts short of war, and provocations do not count as sufficient threats.

You evaluate a valid threat through clear criteria:

• Verify a manifest intent to injure from the adversary.
• Confirm a degree of active military preparation that turns the intent into a positive danger.
• Assess the general situation to ensure that waiting or doing anything other than fighting greatly magnifies the risk.

Israel's first strike in the 1967 Six Day War was a clear case of legitimate anticipation under the condition of a severe and immediate threat. Following false Soviet reports, Egypt put its forces on maximum alert on May 14, 1967, and expelled United Nations Emergency Force troops from the Sinai and Gaza on May 18, 1967. President Nasser announced the closure of the Straits of Tiran on May 22, 1967, and later declared on May 29 that the goal of war would be the destruction of Israel. King Hussein flew to Cairo on May 30, 1967, to sign a military command treaty placing Jordan's army under Egyptian command before actual fighting began with an Israeli first strike on June 5, 1967.

Interventions

Intervention in the domestic affairs of sovereign states is a grave coercive act that always requires heavy moral justification. The legalist paradigm establishes a strong ban on cross-border military actions because citizens possess a right to political self-determination and to suffer only at each other's hands.

Internal political freedom can only be won by a community through its own arduous struggle, making foreign intervention inherently counterproductive for liberty. Following John Stuart Mill and his 1859 essay on nonintervention, you see that self-determination is a process of internal political development. Just as individuals cannot be made virtuous by external force, communities cannot be set free by foreign armies, because true political freedom requires local self-help and endurance.

Humanitarian intervention is justified as a rescue mission when a government engages in massive human rights violations or atrocities that shock the moral conscience. As the fourth revision to the legalist paradigm, extreme tyranny, enslavement, or massacres destroy any presumption of a legitimate political community. Intervening forces must enter into the rescue without claiming political control or violating the core purposes of the oppressed.

In the Cuban insurrection of 1898, Spanish General Weyler instituted forced resettlement policies known as la reconcentración, leading to widespread civilian deaths that shocked American public conscience. A similar moral rescue occurred during the 1971 Indian invasion of East Pakistan and the creation of Bangladesh.

War's Ends

A just war requires morally urgent goals, but once these legitimate ends are achieved, fighting must stop. While traditional military views aim only at the destruction of enemy forces, just war theory establishes limits based on the goals that can rightly be aimed at. Continuing to fight and force soldiers to die beyond that point is a crime akin to aggression.

Unconditional surrender policies are normally overly idealistic, but they are justified against regimes whose inherent criminality threatens deep human values. While realists criticize the Allied demand for unconditional surrender in World War II as a crusading ideology, the right of conquest and political reconstruction exists only when an aggressor state's inherent nature is a standing affront to humanity. In World War II, the Allies demanded unconditional surrender and refused to negotiate with Nazi leaders, committing to occupy Germany and establish a new regime.

3. The War Convention

The conduct of war is governed by strict rules protecting noncombatants and restricting permissible violence. You enter a moral domain where the reasons for fighting no longer determine how you fight.

In the conduct of war, combatants on both sides are treated as moral equals regardless of the justice of their cause.

Because soldiers fight out of loyalty and obedience to their states rather than personal criminal intent, they face each other as moral equals with identical war rights. Rules of engagement apply indifferently to aggressors and defenders alike. Individual soldiers are legitimate targets of attack because they have allowed themselves to be made into dangerous fighters, meaning their risks can be raised to the highest pitch. Unlike civilians who have done nothing to forfeit their rights, a soldier has joined or been conscripted into an enterprise whose class purpose is war.

The war convention is fundamentally grounded in human rights rather than utilitarian calculation or humanitarian kindness. Noncombatants retain their individual rights to life and liberty and cannot be used as instruments for military victory, even in a just war. Prohibitions against attacking civilians or committing sexual violence are matters of strict justice, not charity.

Moroccan mercenary soldiers fighting with Free French forces in Italy in 1943 were given license to rape and plunder enemy territory, an act condemned because it violated the fundamental rights of civilians.

War's Means and Noncombatant Immunity

The traditional principle of double effect permits performing acts with foreseeable evil consequences, such as civilian deaths, provided the military act is legitimate, the primary intention is good, and proportionality is maintained. Originating with medieval Catholic casuists, double effect reconciles the absolute prohibition against targeting noncombatants with legitimate military operations. However, simply intending the military goal while ignoring foreseeable civilian casualties is too permissive and fails to capture the moral obligation soldiers have toward endangered civilians.

The principle of double effect must be revised to require that actors actively seek to minimize foreseeable evil by accepting costs and risks to themselves.

Merely not intending civilian deaths is insufficient under battle conditions. Soldiers have a positive duty to protect innocent people whose lives are endangered by military operations. If saving civilian lives requires soldiers to accept risks, such as conducting patrols or precision bombing at lower altitudes, those risks must be borne up to the point where the military venture is doomed.

Free French air force pilots specialized in low-altitude precision bombing in occupied France to minimize civilian casualties, despite the increased risk to their own lives. Operations resulted in 34 men killed in the first failed commando attempt at Vemork, and 22 Norwegian civilians killed during the later American bombing of the Vemork plant.

You must follow specific logical steps when evaluating operations:

• Verify that the act is good in itself or a legitimate act of war.
• Ensure the direct effect is morally acceptable such as destroying military supplies.
• Maintain a good intention where evil is neither an end nor a means.
• Confirm the good effect compensates for the evil effect under the proportionality rule.

Frank Richards shouted a warning down cellars before throwing bombs, accepting the risk that hidden German soldiers might fire back, in order to avoid the innocent murder of French civilians sheltering below.

Sieges and Blockades

The principle of double effect cannot justify siege warfare because the deaths of ordinary inhabitants are expected and intentional. When a city is encircled and deprived of food, the goal is surrender achieved through the fearful spectacle of civilian dead rather than the direct defeat of the enemy army. Because these deaths are intended to force leadership's hand, they fall outside the protection of double effect, making the traditional exception granted to sieges morally problematic.

During the Roman siege of Jerusalem in 72 A.D., famine consumed whole households, families, and streets filled with dead bodies.

Besieging armies have a moral obligation to open a path for civilian flight, and offering free exit is necessary to clear commanders of responsibility. Locking civilians into a besieged city and systematically starving them is morally equivalent to driving them into a death trap. In dire conditions, people have a right to be refugees, and attacking commanders must allow noncombatants to leave rather than shooting at them.

During the siege of Leningrad, September 8, 1941 is when the last road and rail links to Leningrad were cut, and Field Marshal von Leeb issued an order on September 18, 1941, to use artillery to stop escaping civilians at all costs.

Guerrilla War and Terrorism

Guerrilla warfare fundamentally subverts the traditional war convention by using civilian clothing as a tactical disguise and protective cover. While surprise is a legitimate conventional tactic, guerrillas rely on a double disguise: as peaceful peasants and as citizens of a surrendered state. This erodes the moral and legal understandings of surrender, turning ambushes into acts resembling assassination rather than open combat.

German Captain Helmut Tausend recalled in the documentary The Sorrow and the Pity how French Resistance members disguised as peasants digging potatoes suddenly picked up hidden guns and shot fourteen soldiers.

Guerrillas acquire legitimate war rights not inherently as individual fighters, but derivatively when the local civilian population voluntarily provides them with vital shelter, food, and support. When the people act in complicity with irregular forces, the war rights of a popular rising are passed on to the guerrillas. Without significant popular support, captured guerrillas can rightly be treated as bandits or criminals.

Guerrilla leaders like Mao Tse-tung established strict behavioral codes to mark their fighters apart from bandits and win the crucial trust of the rural population. Mao Tse-tung's famous rules for Chinese communist forces emphasized strict politeness, paying fairly for purchases, and avoiding damage to crops or mistreatment of captives.

• Speak politely.
• Pay fairly for what you buy.
• Return everything you borrow.
• Pay for anything you damage.
• Do not hit or swear at people.
• Do not damage crops.
• Do not take liberties with women.
• Do not ill-treat captives.

The American rules of engagement in Vietnam attempted to separate civilians from guerrillas through warnings, forced displacement, and the creation of free-fire zones. Policies permitted bombing villages that harbored guerrillas after issuing warnings via leaflets or loudspeakers, culminating in forced deportations and the declaration of free-fire zones where remaining inhabitants were presumed hostile.

Jonathan Schell documented how American units receiving small arms fire from a village along Route 18 in Long An province called in artillery and air strikes, resulting in heavy civilian casualties. August 1967 marked a point during Operation Benton when pacification camps became so full that Army units were ordered not to generate more refugees.

You must follow specific tactical rules in these conflicts:

• Bomb or shell a village without warning if American troops received fire from within it.
• Bomb or shell any known hostile village if inhabitants were warned in advance via leaflets or loudspeaker.
• Declare evacuated areas or depopulated zones as free-fire zones where anyone remaining is assumed to be a guerrilla.

Terrorism is defined fundamentally by the random murder of innocent people to destroy national or class morale. Unlike targeted assassination, terrorist activity seeks to spread fear over time by killing individuals solely because of their collective identity, such as nationality or religion, forcing governments to negotiate for safety.

Soldiers in asymmetric conflicts must accept a degree of personal risk to reduce the risks they impose on enemy civilians. Because insurgents intentionally use civilian cover, soldiers must avoid disproportionate force, utilize ground intelligence, and take positive measures like issuing warnings or conducting close engagements rather than defaulting to air strikes.

U.S. forces in Afghanistan under 2010 rules of engagement were barred from calling in destructive air strikes on buildings without verifying the presence of civilians, requiring troops to accept tactical risks.

You must apply these rules during asymmetric operations:

• Warn civilians of impending danger so they can flee.
• Deploy personnel to verify if civilians are inside a contested building.
• Move soldiers onto adjacent roofs to fire directly rather than calling in air strikes.
• Withdraw from an encounter if the tactical risks of engagement are too high.

Reprisals

Reprisals represent a form of radical utilitarian law enforcement in wartime, functioning as deterrence without retribution by punishing innocent people in response to enemy crimes. While domestic justice combines retribution against the guilty with deterrence, international wartime reprisals often target innocent individuals because actual wrongdoers are inaccessible. Defenders of reprisals argue strictly on utilitarian grounds as a necessary means to check enemy excesses, relying on a proportionality rule that limits retaliation to the scale of previous crimes rather than future effects.

In August 1944, French Forces of the Interior command at Annecy shot 80 German prisoners in retaliation for the execution of 80 French prisoners by German authorities.

4. Dilemmas of War

Extreme crises and nuclear weapons test the absolute limits of moral rules, forcing hard choices between survival and ethical purity.

Neutrality

The moral justification for neutrality rests on the protection of innocent citizens from being forced to risk their lives in other nations' wars. Leaders of a neutral state are bound to maintain civilian immunity and cannot treat their people's lives as international resources.

Neutral rights can only be overridden without altering their validity when a genuine supreme emergency threatens the survival of a society. Rushing to violate neutral rights too soon or for mere expediency is unjust.

Supreme Emergency

A supreme emergency is defined by two strict criteria: the imminence of the danger and its horrifying nature. The impending danger must threaten the very survival of a political community and everything decent in human life.

An unprecedented level of evil can justify overriding the war convention to adopt extreme defensive measures.

Nazism represents the outer limit of exigency, serving as the historical touchstone for a true supreme emergency. Britain stood alone against Hitler's triumphant armies during the terrible two years from the summer of 1940 to the summer of 1942.

The justification of supreme emergency expires once the existential threat recedes and other military options become available. Churchill acknowledged in July 1942 that Russian and American manpower and munitions rendered other possibilities open, yet the bombing continued, culminating in the destruction of Dresden in 1945, where 100000 people were killed.

Nuclear Deterrence

The threat of nuclear holocaust has turned supreme emergency into a permanent condition since 1945, where nations adopt immoral deterrence threats to avoid absolute political subjugation.

Nuclear deterrence is morally problematic because it relies on the explicit threat to commit mass murder of innocent civilians. John Bennett noted that a nation prepares to kill 20 million children under deterrent strategy.

Attempts to fit nuclear war into traditional war conventions through tactical weapons and counter-force strategies fail due to extreme collateral damage and high risks of escalation. Henry Kissinger likened limited nuclear war to naval strategy where self-contained units gain the upper hand without occupying territory.

Nuclear weapons remain politically and militarily unusable precisely because nations can plausibly threaten their ultimate use, trapping humanity in an immoral paradox.

5. Responsibility for War

Political leaders, military commanders, and democratic citizens bear distinct levels of moral and legal responsibility for wartime actions.

War and aggression require holding individual political leaders and statesmen morally responsible for their choices. While conditions of war provide excuses like fear, a theory of justice points to the people who owe an accounting for bloodshed. Legal guilt relies on judges, but moral responsibility evaluates blameworthiness based on principles.

Ernst von Weizsaecker served as State Secretary of the German Foreign Ministry from 1938 to 1943 and was eventually sentenced to seven years in prison.

The Ministries Case established that holding office while consenting to murder is a punishable offense. Von Weizsaecker argued that his internal opposition negated his minimal participation. The court held that giving tacit consent through silence while retaining office was a punishable offense.

Democratic Responsibilities

The degree of moral responsibility for evil deeds done by a state increases in proportion to the possibility of free political action within the communal sphere.

In democratic regimes, you have opportunities for positive response, voting, demonstrating, and organizing opposition. The greater these opportunities for free action, the greater your blameworthiness if you remain apathetic, indifferent, or acquiescent to an unjust war.

Soldiers and Officers

Soldiers are personally responsible for their actions within their range of activity. Self-preservation does not excuse violating the rules of war or killing innocent civilians. Soldiers are moral agents who must accept personal risks rather than enhance security by killing innocent people.

Guy Chapman describes a World War I officer who shot a surrendering enemy officer who was handing over field glasses.

Following superior orders does not completely absolve you of responsibility for committing atrocities that are manifestly unlawful. Military discipline creates powerful pressures to obey blindly, but you retain your ultimate humanity and capacity to refuse or evade immoral commands.

During the My Lai massacre, an American company murdered between four and five hundred unarmed civilian old men, women, and children. A few soldiers refused to fire or tried to stop it.

Military commanders hold immense responsibilities to protect the weak and unarmed. They must take positive steps to limit unintended civilian deaths and enforce the war convention.

In July 1944, General Omar Bradley planned the COBRA breakout in Normandy. He utilized massive carpet bombing in an area three and a half miles wide and one and a half deep targeted near St. Lô while deliberately forgoing forewarning to the French civilian population.

In supreme emergencies where collective survival clashes with human rights, political leaders and commanders may be forced to commit murder in a good cause. This leaves them with dirty hands and enduring guilt.

Arthur Harris directed the British strategic terror bombing of German population centers starting in February 1942 until the official end of the strategic air offensive in mid-April 1945. Post-war British leaders deliberately snubbed and dishonored him instead of granting him a peerage.

Conclusion

The moral framework of war integrates the rules of jus ad bellum and jus in bello to restrain state violence and preserve the boundaries of human agency.

You must recognize that political survival never completely suspends moral obligation. The tension between military necessity and human rights persists in every conflict you evaluate. You can apply these practical rules to judge military conduct and moral responsibility:

1. Oppose any war of aggression that violates the territorial integrity and political sovereignty of an independent state.
2. Permit military preemption only when you face a manifest threat of imminent attack.
3. Protect noncombatants from direct attack by treating them as immune to intentional violence.
4. Weigh proportionality carefully so that the collateral destruction you cause remains minor compared to the legitimate military advantage you gain.
5. Reject supreme emergencies only when they demand atrocities so fundamental that they destroy your own humanity.
6. Hold political leaders and military commanders strictly accountable for war crimes while holding democratic citizens responsible for the broader prosecution of unjust wars.

10 Key Ideas

1. War is not a lawless realm of pure realism; it is shaped by a persistent moral vocabulary and shared human judgments.
2. The legalist paradigm structures international morality through six core propositions modeled after domestic law and order.
3. Aggression is the supreme international crime, violating the territorial integrity and political sovereignty of independent states.
4. Legitimate first strikes are justified not by imminent attack or mere preventive fear, but by the presence of a sufficient threat.
5. Humanitarian intervention is justified as a rescue mission when a government engages in massive human rights violations or atrocities that shock the moral conscience.
6. In the conduct of war, combatants on both sides are treated as moral equals regardless of the justice of their cause.
7. The war convention is fundamentally grounded in human rights rather than utilitarian calculation or humanitarian kindness.
8. The principle of double effect must be revised to require that actors actively seek to minimize foreseeable evil by accepting costs and risks to themselves.
9. An unprecedented level of evil can justify overriding the war convention to adopt extreme defensive measures.
10. The degree of moral responsibility for evil deeds done by a state increases in proportion to the possibility of free political action within the communal sphere.