Pacifists always bear the burden of proof. They do so because, as attractive as nonviolence may be, most assume that pacifism just will not work. You may want to keep a few pacifists around for reminding those burdened with running the world that what they sometimes have to do is a lesser evil, but pacifism simply cannot and should not be, even for Christians, a normative stance.

Nonviolence is assumed to be unworkable, or, to the extent it works at all, it does so only because it is parasitic on more determinative forms of order secured by violence. Those committed to nonviolence, in short, are not realistic. In contrast to pacifism, it is often assumed that just war reflection is "realistic." It is by no means clear, however, if advocates of just war have provided an adequate account of what kind of conditions are necessary for just war to be a realistic alternative for the military policy of a nation.

Just war in the Christian tradition

In the Christian tradition, realism is often thought to have begun with Augustine's account of the two cities, hardened into doctrine with Luther's two kingdoms, and given its most distinctive formulation in the thought of Reinhold Niebuhr. Thus Augustine is often identified as the Christian theologian who set the stage for the development of just war reflection that enables Christians to use violence in a limited way to secure tolerable order. It is assumed, therefore, that just war is set within the larger framework of a realist view of the world. With his customary rhetorical brilliance, Luther gave expression to the realist perspective, asking:

"If anyone attempted to rule the world by the gospel and to abolish all temporal law and the sword on the plea that all are baptized and Christian, and that, according to the gospel, there shall be among them no law or sword - or the need for either - pray tell me friend, what would he be doing? He would be loosing the ropes and chains of the savage wild beasts and letting them bite and mangle everyone, meanwhile insisting that they were harmless, tame, and gentle creatures; but I would have the proof in my wounds. Just so would the wicked under the name of Christian abuse evangelical freedom, carry on their rascality, and insist that they were Christians subject neither to law nor sword as some are already raving and ranting."

Luther is under no illusions. War is a plague, but it is a greater plague that war prevents. Of course, slaying and robbing do not seem the work of love, but, Luther says, "in truth even this is the work of love." Christians do not fight for themselves, but for their neighbour. So if they see that there is a lack of hangmen, constables, judges, lords, or princes, and find they are qualified they should offer their services and assume these positions. That "small lack of peace called war," according to Luther, "must set a limit to this universal, worldwide lack of peace which would destroy everyone."

Reinhold Niebuhr understood himself to stand in this "realist" tradition. In 1940 in his "Open Letter (to Richard Roberts)," Niebuhr explains why he left the Fellowship of Reconciliation. He observes that he does not believe that "war is merely an 'incident' in history but is a final revelation of the very character of human history." According to Niebuhr, the Incarnation is not "redemption" from history as conflict because sinful egoism continues to express itself at every level of human life, making it impossible to overcome the contradictions of human history.

Niebuhr, therefore, accuses pacifists of failing to understand the Reformation doctrine of "justification by faith." From Niebuhr's perspective, pacifists are captured by a perfectionism that is more "deeply engulfed in illusion about human nature than the Catholic pretensions, against which the Reformation was a protest."

Just war theory as limit to state action

Paul Ramsey understood his attempt to recover just war as a theory of statecraft - that is, that war is justified because our task is first and foremost to seek justice, to be "an extension within the Christian realism of Reinhold Niebuhr." Ramsey saw, however, that there was more to be said about "justice in war than was articulated in Niebuhr's sense of the ambiguities of politics and his greater/lesser evil doctrine of the use of force." That "something more" Ramsey took to be the principle of discrimination, which requires that war be subject to political purpose through which war might be limited and conducted justly - that is, that non-combatants be protected.

Yet it is by no means clear if just war reflection can be yoked consistently to Niebuhrian realism. Augustine's and Luther's "realism" presupposed there was another city that at least could call into question state powers. For Niebuhr, realism names the development of states and an international nation-state system that cannot be challenged. Niebuhrian realism assumes that war is a permanent reality for the relation between states because no overriding authority exists that might make war analogous to the police function of the state. Therefore each political society has the right to wage war because it is assumed to do so is part of its divinely ordained work of preservation.

"Realism," therefore, names the reality that at the end of the day, in the world of international relations, the nations with the largest army get to determine what counts for "justice." To use Augustine or Luther to justify this understanding of "realism" is in effect to turn a description into a recommendation.

In an article entitled "Just War Theory and the Problem of International Politics," David Baer and Joseph Capizzi admirably try to show how just war requirements as developed by Ramsey can be reconciled with a realistic understanding of international relations. They argue that even though a certain pessimism surrounds a realistic account of international politics, that does not mean such a view of the world is necessarily amoral. To be sure, governments have the right to wage war because of their responsibility to a particular group of neighbours, but that does not mean that governments have a carte blanche to pursue every kind of interest.

"The same conception that permits government to wage war also restricts the conditions of legitimate war making ... Because each government is responsible for only a limited set of political goods, it must respect the legitimate jurisdiction of other governments."

But who is going to enforce the presumption that a government "must respect the legitimate jurisdiction of other governments"? Baer and Capizzi argue that Ramsey's understanding of just war as the expression of Christian love by a third party in defence of the innocent requires that advocates of just war should favour the establishment of international law and institutions to better regulate the conduct of states in pursuit of their self-interest. Yet Baer and Capizzi recognize that international agencies cannot be relied on because there is no way that such an agency can judge an individual government's understanding of just cause: "absent effective international institutions, warring governments are like Augustine's individual pondering self-defence, moved by the temptation of inordinate self-love."

Baer and Capizzi argue that a more adequate understanding of just war will combine a realist understanding of international politics with a commitment to international order by emphasizing the importance of just intention. This means that a war can be undertaken only if peace - understood as a concept for a more "embracing and stable order" - be the reason a state gives for going to war. The requirement that the intention for going to war be so understood is an expression of love for the enemy just to the extent that the lasting order be one that encompasses the interests of the enemy.

My first reaction to this suggestion is: And people say that pacifists are unrealistic? The idealism of such realist justifications of just war is nowhere better seen than in these attempts to fit just war considerations into the realist presuppositions that shape the behaviour of state actors.

The likes of Ramsey, Baer and Capizzi are to be commended for trying to recover just war as a theory of statecraft - that is, as an alternative to the use of just war as merely a check list to judge if a particular war satisfies enough of the criteria to be judged just. Yet by doing so, they have made clear the tensions between the institutions necessary for just war to be a reality and the presumptions that shape international affairs. For example:

What would an American foreign policy determined by just war principles look like?

What would a just war Pentagon look like?

What kind of virtues would the people of America have to have to sustain a just war foreign policy and Pentagon?

What kind of training do those in the military have to undergo in order to be willing to take casualties rather than conduct the war unjustly?

How would those with the patience necessary to insure that a war be a last resort be elected to office?

Those are the kind of questions that advocates of just war must address before they accuse pacifists of being "unrealistic."

Ultimately, I think the lack of realism about realism by American just war advocates has everything to do with their being American. In particular, American advocates of just war seem to presume that democratic societies place an inherent limit on war that more authoritarian societies are unable to do. While such a view is quite understandable, I would argue that democratic society - at least, the American version - is unable to set limits on war because it is democratic.

Put even more strongly, for Americans war is a necessity to sustain our belief that we are worthy to be recipients of the sacrifices made on our behalf in past wars. Americans are a people born of and in war, and only war can sustain our belief that we are a people set apart.

The unreality of war

Realism is used to dismiss pacifism and to underwrite some version of just war. But it is not at all clear that the conditions for the possibility of just war are compatible with realism. At least, it is not clear that just war considerations can be constitutive of the decision-making processes of governments that must assume that might makes right. Attempts to justify wars begun and fought on realist grounds in the name of just war only serve to hide the reality of war.

Yet war remains a reality. War not only remains a reality, war remains for Americans our most determinative moral reality. How do you get people who are taught they are free to follow their own interests to sacrifice themselves and their children in war? Democracies by their very nature seem to require that wars be fought in the name of ideals that make war self-justifying. Realists in the State Department and Pentagon may have no illusions about why American self-interest requires a war be fought, but Americans cannot fight a war as cynics. It may be that those who actually have to fight a war will - precisely because they have faced the reality of war - have no illusions about the reality of war. But those who would have them fight justify war using categories that require there be a "next war."

Pacifists are realists. Indeed, we have no reason to deny that the "realism" associated with Augustine, Luther and Niebuhr has much to teach us about how the world works. But that is why we do not trust those who would have us make sacrifices in the name of preserving a world at war. We believe a sacrifice has been made that has brought an end to the sacrifice of war.

Augustine and Luther thought Christians might go to war because they assumed a church existed that provided an alternative to the sacrificial system war always threatens to become. When Christians no longer believe that Christ's sacrifice is sufficient for the salvation of the world, we will find other forms of sacrificial behaviours that are as compelling as they are idolatrous. In the process, Christians confuse the sacrifice of war with the sacrifice of Christ.

If a people does not exist that continually makes Christ present in the world, war will always threaten to become a sacrificial system. War is a counter church. War is the most determinative moral experience many people have.

That is why Christian realism requires the disavowal of war. Christians do not disavow war because it is often so horrible, but because war, in spite of its horror - or perhaps because it is so horrible - can be so morally compelling. That is why the church does not have an alternative to war. The church is the alternative to war. When Christians lose that reality - that is, the reality of the church as an alternative to the world's reality - we abandon the world to the unreality of war.

Stanley Hauerwas is Gilbert T. Rowe Professor of Theological Ethics at Duke University. His most recent books are War and the American Difference: Theological Reflections on Violence and National Identity and Hannah's Child: A Theologian's Memoir. He will be in Australia later this month to deliver the 2013 New College Lectures.