Is Just War Theory Obsolete?

In an essay that appeared recently on National Catholic Reporter online, Professor Terrence Rynne of Marquette University offered five reasons that support abandoning Catholic Just War Theory and toward what he calls a positive vision of peace:

  • Modern wars have made the just war theory obsolete;
  • The rise of a Christology “from below”;
  • A clearer understanding of how the New Testament relates to contemporary problems;
  • A renewed appreciation of the way the early church practiced Jesus’ teachings on peace;
  • The compelling, thrilling saga of nonviolent action over the 60 years since Gandhi.

In this essay I’m going to address what I consider to be the most important of these reasons—the changing character of war—to see if it really does demand abandoning a millennium-and-a-half old tradition of Just War in favor of a half-century old tradition of non-violence.

Professor Rynne’s argument is that war has evolved in ways that render two of the key traditional criteria of just war—discrimination and proportionality—“null and void.” Whereas during the First World War, he asserts, civilian deaths were a mere 10 percent of total fatalities, “in modern wars, such as the internal conflict in Syria or the U.S. invasion of Iraq, civilian deaths … range from 80 percent to 90 percent of all war casualties.” He concludes from this that, “by the very criteria of the just war theory, in our era there is no such thing as a justified war.” Modern wars have made just war theory obsolete.

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What are we to make of this claim? Well, to begin with, one might ask why, of all the wars that have been fought since Ambrose and Augustine first articulated the basics of Catholic Just War Theory, the baseline for asserting that today’s wars are inherently disproportional and indiscriminate should be the First World War. Why not the Thirty years War (some German states suffered civilian fatalities approaching 40 percent of the total population)? Why not the Hundred Years War (under 200,000 battlefield fatalities out of a total of about 3,000,000 total war-related deaths)? As even a cursory review of wars fought between the years 500 and 2000 indicate, the First World War was a statistical outlier in terms of the proportion of civilian to military fatalities. When judged against most of the wars fought over the past millennium-and-a-half, today’s wars are not particularly indiscriminate or disproportional. Indeed, depending on who is fighting them they may be decidedly less so than ever before.

Perhaps more important, however, is the logically prior question raised by Professor Rynne’s argument: how, precisely, are proportionality and discrimination defined within the CJW tradition? I say logically prior because unless and until we come to a correct understanding of what those two criteria entail (and do not entail) we will have insufficient grounds upon which to assess the empirical claim that contemporary warfare has mutated to the point where it is inherently disproportionate and indiscriminate and, therefore, universally unjust. Let’s take the principle of proportionality first. According to the Catechism of the Catholic Church, this principle requires that “the use of arms must not produce evils and disorders graver than the evil to be eliminated” (CCC 2309). With respect to jus ad bellum, this principle requires that the good expected when taking up arms be greater than the damage anticipated as a result of doing so. With respect to jus in bello, it means that the violence employed to achieve a just cause must not be excessive or needlessly harmful. The principle of discrimination, on the other hand, stipulates that “non-combatants, wounded soldiers, and prisoners must be respected and treated humanely” and that “every act of war directed to the indiscriminate destruction of whole cities or vast areas with their inhabitants is a crime against God and man, which merits firm and unequivocal condemnation” (CCC 2314).

It is important to note, however, that while these principles are intended to limit the use of force, they are not intended to eliminate it. Proportionality is about limiting both the recourse to war and the degree of force actually employed in war. It is not about eliminating recourse to war altogether. Discrimination is about limiting non-combatant casualties. It is not about reducing non-combatant casualties to zero. The underlying logic at play here is the need to strike a balance between military necessity on the one hand and moral obligation on the other. Catholic just war theory recognizes this and provides us with a tool to strike that balance: the law of double effect. This law holds that an act—including an act of war—is just if it meets the following three conditions:

  • the act itself must not be intrinsically evil;
  • the evil effect must not be a desired end but an undesired side-effect of the act; and,
  • the good effect of the act must exceed the evil effect.

If these three conditions are met, an act of war is considered just, even if non-combatants are killed or wounded and even if the rates at which non-combatants are killed or wounded is historically “unprecedented.”

Approached from this perspective, Professor Rynne’s claim that “by the very criteria of the just war theory, in our era there is no such thing as a justified war” seems difficult to sustain. Not only does the empirical evidence not support this conclusion, but his argument seems built on shaky conceptual foundations as well. For Professor Rynne’s claim to be substantiated, we would have to inhabit a world in which no war-making entities were ever able to fight without violating the principles of proportionality and discrimination (as viewed through the prism of the law of double effect). But that is simply not the world we inhabit today. To be sure, there are plenty of war-making entities (both state and non-state actors) out there that operate with little or no regard for the laws of war. But there are also war-making entities (Western states) that have become more attentive than ever to those laws and to key principles such as proportionality and discrimination. For these states, military laws, regulations, technologies and doctrines have all converged around the moral obligation (and even military necessity) of minimizing non-combatant casualties. To the extent that these states and their armed forces are using force proportionally and discriminately in places like Iraq and Syria, they can be said to be fighting those wars justly—even if the same cannot be said of other parties to those conflicts.

This does not mean, of course, that Western militaries never kill or wound non-combatants. But that is a canard. The point is that, not only do Western militaries not deliberately target non-combatants, they go to great lengths to avoid putting them at risk. For these states and their armed forces, there is indeed such a thing as a justly fought war. The changing character of war, therefore, has not made just war theory obsolete. In fact, quite the opposite: it is now more necessary than ever.

(Photo credit: Alessandro Bianchi/Reuters)


  • Andrew Latham

    Andrew Latham is a professor of political science at Macalester College in Saint Paul, Minnesota for the past two decades. He is the author, most recently, of Theorizing Medieval Geopolitics: War and World Order in the Age of the Crusades published by Routledge in 2012, and The Holy Lance, his first novel, published by Knox Robinson.

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