Warfare is as old as humanity itself. No intervening philosophy, religion, or corrupting civilization had to enter the scene to convince man to use violence to obtain his ends or satisfy his urges. However, the idea of standards and rules that ought to govern the start of a conflict as well as its execution is a thoroughly modern idea.
Just war theory is a Christian innovation. While the modern philosophical tradition traces back to the ancient Greeks, the notions of binding moral principles that should dictate a certain military policy is a result of great Christian thinkers like Augustine, Gratian, Aquinas, and Grotius.
Consider the contrast between the martial values espoused by the Athenian delegation in the Melian Dialogue and the martial values found in Aquinas’s Summa Theologica.
In the first work, the Athenians engage in a discussion with the people of Melos in which they articulate a chilling version of the “might makes right” argument. In the latter work, Aquinas articulates stringent moral criteria that must be satisfied before war can occur.
While Thucydides does not appear to be sanctioning the views of the Athenians, the passage is still illustrative of the governing ethics of powerful states throughout most of the world’s history.
The idea that a stronger power would voluntarily suppress their military advantage in deference to justice cuts against the grain of human nature. So lasting an impact has this just war tradition played in world affairs that now even evil regimes attempt to cloak their moves in the guise of just cause. What just cause was claimed by Genghis Kahn? Did Hengist and Horsa feel the need to justify their conquests?
The answer is no, because these men did not feel the constraints of Christian religio-moral precepts. We often operate under the illusion of “progress” through history whereby our own times are the most enlightened and wise.
We often think that warfare in the West is more humane now simply because we left behind all that barbarism and those “medieval” practices. This is a powerfully pernicious idea in general, but especially in light of our experience of the 20th century with its accompanying displays of “advanced” inhumanity.
It is not education, free thought, rationality, or Hegelian progress that accounts for the just war tradition. It is the power of Christ’s impact on culture and the hearts of mankind that can lead to a reduction in unjust war. It is beyond the scope of man’s unaided nature to love justice, seek mercy, and walk humbly before God. But with the help of his sanctifying power operating on our thoughts, we may forgo unjust gain and conduct those wars that must be fought with a respect for human life.
