War as calculation, not righteousness: is there any place for justice in war, or only for advantage?

Sun Tzu, answered from the texts and cited to the page.

The position in brief

War is decided by calculation, not by the justice of the cause. No ruler should put troops into the field to gratify his own spleen, and no general should fight from resentment; anger turns to gladness and wrath to contentment, but a state once ruined cannot be restored, nor the dead brought back to life.123 The question before battle is not whether the cause is righteous but whether the reckoning is favourable.4

Sources

  1. No ruler should put troops into the field merely to gratify his own spleen; no general should fight a battle simply out of pique.
    The Art of War
  2. But a kingdom that has once been destroyed can never come again into being; nor can the dead ever be brought back to life.
    The Art of War
  3. Anger may in time change to gladness; vexation may be succeeded by content.
    The Art of War
  4. When the higher officers are angry and insubordinate, and on meeting the enemy give battle on their own account from a feeling of resentment, before the commander-in-chief can tell whether or no he is in a position to fight, the result is ruin.
    The Art of War

Where the argument is made

  • The Art of War, ch. I on the five factors and the pre-war reckoning
  • the warnings against fighting in anger and against the ruler who moves his army from wrath

How the argument was received

Read as the founding text of strategic realism; contested by every tradition that makes the justice of the cause the first question of war.