War and Peace

Chinese military strategy

War is a matter of vital importance to the state, to be studied with utmost care and never entered lightly. The acme of skill is to subdue the enemy without fighting, winning through foreknowledge, deception, and the shaping of circumstances so that victory is decided before battle is joined. Prolonged war impoverishes the state, so the wise commander seeks swift, economical results and attacks the enemy's strategy and alliances before his armies.

The Art of War.

Ancient Greek historiography / realism

War springs from the interplay of fear, honour, and interest among states, and the truest cause of the Peloponnesian War was Sparta's fear of growing Athenian power. In the Melian Dialogue the strong take what they can and the weak suffer what they must, exposing the harsh logic of power politics. War strips away the veneer of civilization, and Thucydides recorded it as a 'possession for all time' from which later generations might learn.

History of the Peloponnesian War.

Christian (Patristic)

War is a tragic consequence of sin, but a Christian may fight in a just war waged by legitimate authority for a just cause, with the true aim of restoring peace. The right disposition matters as much as the act: even in war the soldier must not be moved by cruelty or lust for domination but by love that seeks the wrongdoer's correction. Peace is the tranquillity of order, the ultimate object even of those who make war.

The City of God; Contra Faustum.

Scholastic just-war theory

A war is just only if three conditions are met: it is declared by legitimate authority, it is waged for a just cause such as redressing a wrong, and those who wage it have a rightful intention aiming at good and the avoidance of evil. Aquinas systematized the just-war criteria within his broader account of charity and the common good. Even a just war remains bound by the demands of justice and may not be pursued with an intention corrupted by hatred or greed.

Summa Theologiae, II-II, q. 40.

Renaissance political realism

A prince should have no other object than war, its methods and discipline, for it is the art proper to one who commands. Strong states rest on their own arms — a citizen militia — rather than on mercenaries and auxiliaries, who are useless and dangerous. War is a permanent feature of political life to be prepared for in peace, and the prudent ruler treats questions of security with clear-eyed realism rather than pious illusion.

The Prince (1513); The Art of War (1521).

Natural law / international law

Even between sovereign states there is a binding law grounded in nature and the society of humankind, which would hold 'even if we were to concede that there is no God'. War is not lawless: there are just causes for resorting to it and enforceable limits on how it may be waged, sparing the innocent and honouring agreements and treaties. Grotius laid the foundation of modern international law, insisting that relations among nations are subject to right, not mere force.

On the Law of War and Peace (1625).

Social contract / realism

In the absence of a common power to keep them in awe, men and states are in a condition of war 'of every one against every one', where there is continual fear and danger of violent death. Peace among individuals is achieved only by erecting a sovereign, but between sovereign states no such overarching power exists, so international relations remain a permanent posture of war. The first law of nature is to seek peace where it can be had, and to use the advantages of war where it cannot.

Leviathan (1651), ch. 13.

Critical philosophy

Perpetual peace is not a naive dream but a rational duty that can be approached through definite conditions: republican (representative) constitutions, a federation of free states, and a cosmopolitan right of universal hospitality. Because in republics the citizens who bear war's costs must consent, such states are far less prone to war. Standing armies should in time be abolished, no state should forcibly interfere in another, and the very antagonism of nations may drive humanity toward a lawful international order.

Toward Perpetual Peace (1795).

Modern military theory

War is not an independent thing but the continuation of policy by other means; it is an act of force to compel the enemy to do our will, always subordinate to political purpose. Real war is dominated by friction, chance, and the 'fog' of uncertainty, and shaped by a 'remarkable trinity' of primordial violence, the play of probability and the commander's genius, and rational policy. Though war tends in theory toward the absolute, in practice it is limited by political aims and circumstance.

On War (1832, posthumous).

Christian anarcho-pacifism

History is not made by the will of great commanders but by the sum of countless individual actions, so the 'genius' of a Napoleon is an illusion cast over forces no one controls. War is an evil that reveals the emptiness of power and the folly of believing rulers direct events. In his later writings Tolstoy embraced radical nonresistance to evil by force, drawing on the Sermon on the Mount to condemn all violence, war, and the coercive state.

War and Peace (1869); The Kingdom of God Is Within You (1894).

Nonviolence (satyagraha)

Nonviolence (ahimsa) is not passivity but the most active force there is, and satyagraha — the firm grasping of truth — confronts injustice through disciplined suffering rather than retaliation. Means and ends are inseparable, so a just order can never be founded on violence; peace is built by refusing to cooperate with evil while bearing its blows. Gandhi turned this creed into a mass political method that helped end colonial rule and inspired later movements for justice.

Hind Swaraj (1909); An Autobiography: The Story of My Experiments with Truth.

Contemporary just-war theory

Just-war theory rests on two distinct sets of judgments: the justice of going to war (jus ad bellum) and the justice of conduct within it (jus in bello), which must be assessed separately. The 'war convention' protects noncombatants through the principles of discrimination and proportionality, so that even a just cause cannot license attacks on the innocent — except perhaps in the rare 'supreme emergency'. Walzer revived the moral vocabulary of war through concrete historical cases rather than abstract theory.

Just and Unjust Wars (1977).