Terrorism and 'just war'; an old tradition, new challenges: Moral challenges

November 14, 2001

The mainstream of Christian ethics has contended that there can be a legitimate or “just” use of military force—legitimacy being determined by a variety of factors, such as the presence of a “just cause,” “right authority,” “last resort,” and the use of “means proportional to the end,” to cite some of the traditional language of just war thinking. In the wake of the terrorist attacks of September 11, Christian thinkers in the U.S. have again drawn on the vocabulary of this tradition as they ponder the proper response to terrorist acts. At the same time, many commentators—including some of the following four—have acknowledged that the categories of just war thinking are not easily adapted to the challenge now facing public authorities in the U.S.—the challenge of responding not to an aggressive state but to unidentified individuals whose aim is to spread terror.


The United States is said to be “at war.” There certainly is no question that it has been viciously attacked on its own soil; there is no question that it is now engaged in sustained and large-scale military operations beyond its borders. From the perspective of the just war tradition, however, the nature of this war raises intellectual and practical moral challenges.

Throughout its modern history, just war has been premised on the concept that war is a conflict among states; yet in this “war” the primary conflict (at least initially) is with al-Qaeda, a nonstate actor. Concepts of victory and reasonable hope of success are usually conceived of in terms of conflict with a state possessing authority capable of surrender, of negotiating terms, and of exercising effective authority over its surrendered forces to ensure respect for cease-fires and surrenders. All these elements are conspicuously lacking, at least at this stage in the current conflict. These, and many other distinctive elements of this conflict, pose challenges to existing moral frameworks for assessing the use of military force.

Although space will not permit exploration of the point here, it is important to note that Christian thought about just war predated the rise of the modern state system in the 17th century, and rests on fundamental moral principles not essentially tied to that system. Instead, it was concerned only to locate the competent authority to redress wrong and repel violence. Neither a presumption against war nor the existence of sovereign states is fundamental to the just war tradition throughout its long history; use of force to repel evil is. It is worthwhile to recall that the first exercise of U.S. military power well beyond its borders was the repression of piracy by the Barbary Pirates on the high seas—not an interstate conflict at all. Instead, the U.S. used force for what in modern parlance one might call “international order” considerations.

With these qualifications, we come to the central question: In what senses, then, are “war” and the ethical standards attached to it transferable to the present conflict?

First, while the just cause for the use of military force in this instance is not interstate aggression, there can be no question that violence of the scale of the September 11 events justifies use of military force in response and in order to eliminate if possible the agents’ capability to launch similar attacks in the future.

The fundamental moral concern to protect innocent human life is not, however, overridden, even in the face of such violence. This means that any morally appropriate military response must still address just war issues such as “reasonable hope of success” and proportionality. The practical implications of these points are clear, even if somewhat unpalatable for those not accustomed to thinking in practical terms about military matters.

First, the ability to use military force with due respect to such considerations is absolutely contingent on the quality and quantity of the intelligence information available. Those concerned with the moral dimensions of this “war” wish above all for very, very good spies. Only that capability will make it possible to locate with precision the targets of legitimate attack.

Second, while use of the military instrument of national power is clearly justified in this circumstance, a prudent policy will recognize that military force is only one arrow in a fairly well-stocked quiver of coercive instruments. Another critical element is intergovernmental cooperation to choke off the terrorists’ money supplies. This will involve taking or freezing assets directly when they can be identified, but also destroying drug crops and blocking the transfers of funding to al-Qaeda and the religious “education” institutions that provide its recruiting base. Such efforts must be systematic and consistent, even if they target states that claim to be our friends—including some in possession of natural resources vital to our prosperity and power (a fact which, to put it mildly, greatly complicates matters).

To some degree, the ideological and religious beliefs that underlie al-Qaeda’s terrorism lie beyond the reach of our power. The central object of attack cannot, therefore, be the ideology; it can only be the organization, funding and communication that give those ideas practical effect. Occasionally, those elements will be amenable to direct conventional military attack; more often, attack upon them will be covert, monetary and legal. In short, this will be a war in which the public military aspects of the conflict may well be a relatively small proportion of the effort.

The “right intention” element of just war has important implications in this conflict as well. Mere revenge is not a worthy or morally acceptable motive for our military efforts. Classically, the legitimate end of war is a restoration of the status quo ante, the situation as it existed before the conflict commenced. What would that standard mean in a war such as this? Unlike conventional war, it obviously does not mean that the other nation’s tanks are back on their side of the border. Even in that conventional case, there is broad permission not only to restore the literal location of forces, but also to build in security guarantees that make it unlikely they will commit aggression again.

Similar considerations should guide our thinking in this case. It will not be enough merely to eliminate the particular bad actors responsible for these particular acts of terror. To the greatest extent possible, the U.S., in cooperation with other nations, must attempt to build an environment which enables the securities and comfortable routines of the pre–September 11 environment to return to American life. At a minimum, this means increased international cooperation to share intelligence on terrorist groups, to starve them of funding and “safe harbor” from other states, and the will to repress and eliminate them preemptively whenever intelligence is sufficient to warrant such actions.

Space does not permit exploration of the many additional important issues to be considered as we proceed with our “war.” The intellectual and practical challenge, however, is clear: to retain the core moral elements of the just war tradition, even as we acknowledge that they must be rethought, adapted and extended to cover our genuinely novel strategic situation.


See the other contributions to this conversation, by:

Glen Stassen
Jean Bethke Elshtain
James Turner Johnson