Just-war theory allows for no blank checks in Ukraine

By Phil Lawler ( bio - articles - email ) | Aug 18, 2023

When I teach an undergraduate course about the Church’s tradition of just-war teaching, I always emphasize how the moral questions are wrapped up in prudential judgments. No one has perfect information about the strengths and intentions of potential adversaries. No one can guarantee the outcome of a given diplomatic or military strategy. So it is rarely possible to say, with complete certainty, that this or that conflict was either just or unjust. And the difficulty of rendering that sort of apodictic judgment is exponentially greater when the battle is raging, the “fog of war” has settled in, and the information coming from the front is filtered through competing propaganda mills.

Just-war theory provides an indispensable framework for debates about the morality of a conflict. But it does not lend itself to incontrovertible decisons, because any judgment will be based on analyses and prognostications that are always debatable. So although I have serious concerns about the wisdom of American involvement in the war in Ukraine—which I discussed in a 3-part series earlier this year—I cannot claim infallibility, and I respect the opinions of serious thinkers like my friend George Weigel, who has strongly supported the effort.

But Weigel goes too far in a column for First Things, in which he complains that “many Catholic just-war thinkers accept the notion that the just-war tradition begins with a ‘presumption against war.’” I cannot name a respectable just-war thinker, past or present, who does not begin with that presumption. War is hell, as General Sherman said, and no sane combat veteran has gainsaid him. The Fifth Commandment itself requires a presumption against war, and a heavy one.

This does not imply, by any means, that a correct understanding of the just-war tradition leads to pacifism. The entire purpose of that tradition is to guide political leaders through the moral calculations that can, in extreme circumstances, justify the use of force. Sometimes the negative consequences of not engaging in military combat are so deleterious that they outweigh the undoubted evils of war. In such cases the principles of ius ad bellum may not only justify but even require warfare.

In his essay Weigel introduces another principle, which he calls ius ad pacem, and defines as “an obligation to build a just peace in the aftermath of war. That obligation certainly exists. But it cannot be invoked to jump over the other requirements of ius ad bellum and ius in bello. Here I am thinking primarily of the demands of proportionality. Is the injustice being confronted grave enough to justify the loss of many human lives? Are the military strategies designed to achieve the greatest good while doing the least damage? Is there a realistic prospect for military success? Without the discipline imposed by those moral considerations, the ius ad pacem could be invoked to justify an unrestrained military campaign, based on the often illusory (but always seductive) promise that military victory will bring a brighter future—in other words that the end justifies the means.

A just war, by contrast, is always a limited war. (In some cases, such as World War II, the conflict may seem unlimited because the worldwide stakes are so high. Even then, a proportional response is mandatory.) The goal is not to annihilate the foe but to prevent him from doing further harm. If they apply just-war principles, leaders are constantly assessing how they might achieve their goals with a minimum of bloodshed, and as soon as those goals are met—or can be met through peace talks—the military campaign should end.

Weigel opens his column by citing the argument of Carl von Clausewitz that “war is the extension of politics by other means.” That quotation is better rendered as “the extension of politics with other means.” The German word mit allows for either translation, but the great Prussian theorist goes on to say that “politics does not cease with the war itself.” In other words warfare is not politics by other means—which could imply that ordinary political dealings end when the shooting starts. Warfare is politics with other means—with another approach to complement the usual tactics of foreign affairs. Clausewitz goes on to caution in the following paragraph that “war can never be separated from politics,” lest “we have left before us a senseless thing without an object.”

What is the object of the war? If that object can be attained peacefully, then war cannot be justified. Can it be attained, realistically, with a heavy application of military force? At what cost? All these questions remain valid, even after we have decided—if we can decide—which side we favor in a conflict. Ius ad pacem is a valid consideration but not a blank ticket.