During the months of debate leading up to the Iraq war much could be heard from across the political spectrum on the theory of "just war." Opponents of the Bush administration insisted that, because Saddam Hussein had not attacked the United States or its allies, war to overthrow him or even disarm him would not meet the criteria for a "just war." In order for a war to be justified, they insisted, it would at the very least require some sort of imprimatur from the United Nations. On the other hand, supporters of the administration countered that current realities—the existence of worldwide terrorist networks, and of "rogue states" with weapons of mass destruction—required a looser definition of what is permissible under that theory.

Of course, what the two sides have in common is their insistence that just war theory is valid and necessary. In doing so, however, they are proceeding from premises that may be on their way to becoming irrelevant.

Just war theory has its origins in the writings of St. Augustine, who was faced with the daunting task of trying to apply the teachings of Jesus Christ to his own age. Christ, after all, had eschewed violence (except for that unfortunate "money-changers in the temple" incident). He told his followers to "resist not evil," and to "turn the other cheek" when attacked. On the night of His arrest He rebuked one of His companions for trying to defend Him by force. "Put your sword back into its sheath," He told the man, "for all who take the sword will perish by the sword."

Yet Christ was speaking to a population that was subject to the Roman Empire. His audiences were looking for an earthly Messiah who would liberate them from their pagan oppressors. Clearly what Jesus was saying was that it was futile—indeed, suicidal—to resist the Roman authorities. The problem for St. Augustine was to try and make these sentiments relevant to the world of the early fifth century, and a very different world this was. No longer was Christianity a tiny, persecuted minority; rather, by the end of the fourth century it had become the official religion of the mightiest empire the world had ever seen. Indeed, imperial authorities were now using force to destroy the old pagan religion that had once formed the spiritual backbone of the empire.

The dilemma concerning Christ’s teachings on violence became readily apparent when a young man wrote to Augustine asking whether it was proper for a Christian to serve in the Roman army. In other words, was it legitimate to wage war in pursuit of Christian ends? Augustine’s response was that this was acceptable, but only with the certainty that the cause was just, and even then only with the greatest reluctance. In the end, he wrote, the "injustice of the opposing side is what imposes the duty of waging wars."

Later thinkers, from St. Thomas Aquinas to Hugo Grotius to Michael Walzer, would develop this idea further, yet all of them shared the same essential premise—war is horrible, and is therefore only conscionable under extreme circumstances, and only as a last resort.

This seems like a commonsense proposition, and, indeed, for nearly all of human history it was essentially non-controversial. For centuries war brought not only violent death but also the related horrors of famine and plague as campaigning soldiers pillaged towns and burned crops. Moreover, with the industrial revolution came the ability to kill people in increasingly large numbers in shorter and shorter periods of time—culminating, of course, in the development of nuclear weapons. Given the circumstances, it was only natural that theologians and moral philosophers would only sanction war under extraordinary conditions.

But what would happen if war ceased to become so horrible? What if technology continues to develop in such a way that the cataclysmic effects traditionally associated with war no longer materialize? This is not idle speculation—the war in Iraq was remarkable for how little serious damage it caused. There were casualties to be sure, but these were infinitesimal when compared to similar operations in military history. Predictions by some opponents of the war that civilian deaths would amount to the hundreds of thousands were off by a magnitude of a hundred, if not a thousand. Tellingly, in the days after the fall of Saddam Hussein the chief concern of residents of Baghdad—some of whom lived just blocks away from government installations devastated by coalition forces—was not to bury their dead and rebuild their homes, but to demand that their electrical service be restored. In many parts of the United States, this is roughly the same response that comes in the wake of a particularly bad thunderstorm.

This appears to be a trend that is likely to continue in the coming years. Many recent developments in weapons technology emphasize keeping civilian casualties to a minimum. Moreover, it may eventually become possible to defeat an enemy’s armed forces without actually killing anyone. The May 2003 issue of Popular Science highlights the increasing use of non-lethal weapons—"sponge-tipped rounds," "pain beams," and "slippery foams"—that can temporarily immobilize or disable enemy soldiers without doing them any real bodily harm. Is it so far-fetched to imagine that in the not-so-distant future a tyrant like Saddam Hussein might be overthrown in a military operation in which nobody dies?

The human cost of the Iraq war, when compared to the number of lives lost had Saddam Hussein remained in power, already seems remarkably small. Even honest opponents of the war will have to admit that so-called "peaceful" economic sanctions enforced over the twelve years after the first Gulf War killed many, many more Iraqis than did the war. If the costs of military action continue to fall, the whole concept of just war might well become irrelevant. There might come a time when Americans no longer hesitate to remove murderous dictators for fear of the consequences for innocent civilians. And when that day comes, it will not be U.S. military intervention that requires justification—it will be American inaction in the face of evil. Then, perhaps, we will see the replacement of just war theory with just peace theory.

John Moser is an assistant professor of history at Ashland University and an Adjunct Fellow of the John M. Ashbrook Center for Public Affairs.