In 1983 one of the most powerful nations in the world, the United States, fought one of the weakest, Grenada. Even in this lopsided affair, which lasted only a few days, twenty innocent people were killed when United States fire hit a mental hospital. The American people received this news with equanimity, in that they had become inured to the slaughter of innocent people, say by the Nazis against the Jews or by the Soviets against their own people, but also by their own government’s bombers at the end of World War Two or by its lieutenants at My Lai. Nuclear weapons notwithstanding, the issue of noncombatant immunity poses the greatest threat to the continued efficacy of the just war theory.
At present James Turner Johnson, of Rutgers University, editor of The Journal of Religious Ethics, offers perhaps the most sophisticated treatments of just war theory, specifically Christian just war theory, and he astutely claims that a primary task of the Christian ethicist is to reintroduce acquaintance with what has been lost in Christian tradition (HT, 300). But what is the Christian tradition regarding noncombatant immunity? Obviously no answer to this question can afford to ignore St. Thomas Aquinas, but exactly was his position on this issue? The American Catholic Bishops and various Thomistic textbooks, acting as distilling agents for the various drops of Catholic tradition, imply that for St Thomas it is always wrong to intentionally kill noncombatants, which leaves open the possibility of killing some noncombatants if such killing is compatible with the proportionality dimension of the principle of double effect.