Just war theory

Just war theory
Name	Just war theory
Caption	Artistic depictions of justice, such as Jacopo Zucchi's Allegory of Justice, have long been associated with ethical debates on statecraft and conflict.

Just war theory is a doctrine of military ethics with origins in Western philosophy and Christian theology that seeks to ensure war is morally justifiable through a series of criteria. It is traditionally divided into the justice of going to war, the just conduct within war, and the responsibilities following conflict. The framework has been employed by statesmen, theologians, and international bodies to evaluate conflicts from the Peloponnesian War to contemporary interventions.

Origins and historical development

The earliest systematic explorations originate in the works of classical philosophers, notably Cicero in De Officiis and Aristotle in Politics, who debated the relationship between virtue and state violence. These ideas were substantially developed within Christian theology, particularly by Augustine of Hippo in works like The City of God, who argued that war could be a tragic necessity for preserving peace. The medieval period saw the doctrine codified by scholars such as Thomas Aquinas in the Summa Theologica, integrating Aristotelian ethics with Christian doctrine during events like the Crusades. The Peace of Westphalia and the writings of Hugo Grotius in De Jure Belli ac Pacis later secularized the concept, influencing modern international law and institutions like the United Nations.

Core principles: jus ad bellum

The criteria for justly entering war require that the cause is righteous, typically limited to self-defense against aggression as outlined in the UN Charter, or humanitarian intervention. A competent authority, such as a sovereign state or the United Nations Security Council, must declare war, moving beyond private vendettas. There must be a right intention to secure peace, not for territorial expansion or economic sanction retaliation, and a high probability of success to avoid futile suffering. The conflict must be a last resort after all diplomatic options like those pursued at the Congress of Vienna are exhausted, and the anticipated good must be proportional to the expected evils.

Core principles: jus in bello

Once war begins, just conduct demands discrimination between combatants and non-combatants, prohibiting direct attacks on civilians as seen in the bombing of Dresden. The principle of proportionality requires that the military advantage gained from an action outweighs the collateral damage, a calculation central to debates over the atomic bombings of Hiroshima and Nagasaki. Methods of warfare are also restricted, forbidding means that cause unnecessary suffering, such as chemical weapons banned by the Geneva Protocol. These rules are enshrined in treaties like the Geneva Conventions and are upheld by bodies like the International Committee of the Red Cross.

Core principles: jus post bellum

This emerging category addresses justice after conflict, demanding a just peace that avoids vindictive measures like those of the Treaty of Versailles. It includes responsibilities for reconstruction, war crimes accountability through tribunals like the International Criminal Court or the Nuremberg trials, and proportional compensation. The goal is to establish a stable political order, as attempted in post-war Germany and Japan following World War II, and to facilitate reconciliation, preventing a return to cycles of violence as seen in the Yugoslav Wars.

Modern applications and criticisms

The theory has been applied to assess interventions such as the Gulf War, the NATO bombing of Yugoslavia, and the War in Afghanistan (2001–2021). Critics, including proponents of pacifism like Leo Tolstoy and modern realists, argue it can be manipulated to justify wars of interest. The rise of asymmetric warfare with non-state actors like Al-Qaeda and challenges from cyberwarfare and drone strikes test traditional distinctions. Organizations like Amnesty International and the International Court of Justice frequently engage with its principles in legal and humanitarian assessments.

Key theorists and philosophical influences

Early foundational work was done by Augustine of Hippo and Thomas Aquinas, whose frameworks were expanded during the Scholasticism period. The early modern era was shaped by Francisco de Vitoria of the School of Salamanca regarding colonial conquests and Hugo Grotius, a father of international law. In the 20th century, thinkers like Michael Walzer in Just and Unjust Wars and institutions like the United States Conference of Catholic Bishops have provided contemporary analysis. The tradition engages with wider philosophical ideas from Immanuel Kant's Perpetual Peace: A Philosophical Sketch to the legal positivism of H. L. A. Hart.

Category:Military ethics Category:Political philosophy Category:International law