To work through the prudence of a boots-on-the-ground fight against ISIS, permit me to list the criteria for just war (here, I’ll only address jus ad bellum or justice related to going into war, setting aside jus in bello, or the principles of moral action within war) and ask whether the current ISIS crisis deserves more aggressive military action.
1. Just cause. Here, we ask whether the purpose is selfish or in defense of the innocent. ISIS has demonstrated an unflinching willingness to execute, torture, and enslave innocent people from various backgrounds. While there might be economic interests behind the scenes, to fight ISIS would not be to trade blood for oil. It would be to respond to the call to oppose manifest evil.
2. Competent authority. This criterion seeks to ensure that wars are declared by lawful means and with governments and coalitions that proceed along the lines of international law. Unlike some past unilateral involvements, things are shaping up such that this would be a sincere coalition of multiple nations like France and Russia. Likewise, I believe, despite the national fatigue related to foreign entanglements, it would seem possible to muster bipartisan support for serious involvement.
3. Comparative justice. With this criterion, we ask whether the lives and values at stake justify the inevitable consequences of war: death, displacement and destruction. In the case of ISIS, it seems that violent intervention is comparatively better than the current situation, which already involves death, displacement and destruction. We aren’t dealing with stifling Sharia laws, but with terrorism and mass executions carried out by ruthless ideologues.
4. Right intention. This criterion asks us to pursue reasonable and morally admirable goals. We must not seek, for instance, the unconditional surrender or extermination of a people group. We must have a just, peaceful goal in mind. This criterion is tricky, since it makes most sense in the case of wars between discrete nations. Here, unfortunately, we would need to seek a sort of unconditional surrender, but only to the extent that it is a surrender of terrorist planning and activity.
5. Last resort. This criterion is extremely important, and too often ignored. We might not have had to experience our current popular opinion fatigue, had we been a bit more frugal with our expenditure of resources and soldiers’ time away from home. Nonetheless, there is no time for diplomacy. ISIS has declared as much. Innocent people are being mowed down. It seems that war in this case, despite it’s nontraditional form, is indeed our only remaining option.
6. Probability of success. This criterion, like “right intention” is problematic because it makes more sense with respect to wars between nations. If, for instance, Canada wanted to invade the U.S. and make it part of a new empire in the Western Hemisphere, and if, for instance, they had built up enough military machinery to make a march through the Dakotas effortless, there might be an argument that we should simply surrender before countless lives are lost. People might not like socialized medicine and whatever else the Canadians were to bring with their new world order, but the stakes would not be so dire that fighting an impossible war would be worth it. What about ISIS? It seems that terrorism and insurgency are like the Lernaean Hydra, a serpent with multiple heads that, when severed, grow into even more heads. Thus, to fight might be to escalate and provoke increasing attacks. Fair enough. But there seems to be no reason a priori to assume that a patient counter-terrorism effort couldn’t work, especially when there are at least some identifiable locations where ISIS leaders congregate. Moreover, the fight is already on, and were the wicked to have their way, the implications would be dire indeed.
7. Proportionality. With this final criterion, we must attend to the many costs involved in going to war. Could our national economy sustain a protracted endeavor? How many more people would be displaced along the way? Which countries, if any, would be willing to take in the refugees created by increased warfare? Perhaps, if there were only a few terrorist incidents in regionally isolated spots, we might not want to stir anything up. Unfortunately, however, things have already been stirred. We could hardly cause more disruption than ISIS has already caused, and will continue to inflict on the world.
Therefore, with a heavy heart, I must conclude that enhanced military action—call it a full-fledged war if need be—is justifiable against ISIS. I believe that Christians should usually be the last to clamor for war. We must also resist unjust short-cuts like indiscriminate bombings and torture. But when innocent people are suffering, to ignore their plight and reject direct involvement outright is no virtue. Some criteria from just war theory are difficult to apply (such as #4 and #6) because “war” with ISIS would not be traditional. Moreover as the video (below) illustrates: it is not easy to figure out who to back and how to back them in this complicated region. That question calls for wisdom and attention to good intelligence, but it is not the question at hand. What we're after here is the question of whether, if we do finally get a sense of how best to intervene, we would be just in our participation in violence.
In any case, I believe that even a person who is generally a pacifist might want to override their general principle of nonviolence for this particular situation. Every once and a while, kind-hearted people need to awaken to real threats, stand up, and face those threats with the necessary resolve. They need to do this for the defense of the innocent. With ISIS, we are dealing with one of the greatest threats to decent civilization in centuries. People of principle can’t let a couple decades of arguably misguided foreign policy to cloud our calling at this hour. Peace should of course be our goal. Today, alas, we are not at peace. The mortal enemies of decency have already declared war.