When it comes to war, Christians generally adhere to either the pacifist, holy war and just war tradition. The just war tradition takes a bit of time to flesh out, so I'll return to it in a later post. Suffice for now is to say that advocates of the just war tradition either view war as a necessary evil or as moral good that sometimes calls on Christians to fight on behalf of the rights of others. However, while just war advocates often disagree over whether war is a necessary evil or as a moral good, they do tend to agree on a series of guidelines as to when a war can be fought and as to how a war must be fought in order for it to be a just war. In other words, not only do the reasons for going to war need to be just, so do the means for fighting a war.
The holy war tradition differs from the just war tradition in at least two ways: success does not have to be probable (to fail in a holy war is sometimes seen as a moral victory, while to die in a holy war is often viewed as a quick way to heaven) and enemies have no rights (in a holy war genocide is often the norm). Holy warriors also believe that a holy war is divinely sanctioned (known through some form of revelation). Christians, of course, haven't cornered the market on the holy war tradition. Other cultures such as ancient Israel and certain strands of Islam have embraced it as well. Within the Christian tradition, a holy war hasn't been declared since the 12th-century (President Bush's use of the word "crusade" notwithstanding).
Contrary to attempts by critics to lump all pacifists together, there are actually several pacifist traditions. In fact, the late Mennonite theologian, John Howard Yoder, identified at least 22 different forms of pacifism. For simplicity sake (plus the fact that I am not the scholar that Yoder was) I will limit the following discussion to three of the more common types of pacifism: 1) What would Jesus do (WWJD) pacifism, 2) instrumental pacifism and 3) eschatological pacifism. WWJD pacifism is relatively simple to understand and can be illustrated by a story told by Baptist theologian Tony Campolo. During the Korean War Campolo was called into the draft board office for a preliminary examination by an army colonel, who asked Tony if he was flying over enemy territory whether he would be able to drop a bomb. Tony replied, "I'd have to ask myself, "If Jesus were in my shoes, would he drop a bomb?" To which the officer retorted, "That's the dumbest thing I ever heard! Everyone knows that Jesus wouldn't drop any bombs." So, Tony concluded that he wouldn't be able to drop any bombs either.
Critics of of this tradition argue that it is too individualistic in that it ignores the claims that the communities in which we live (and move and have our being) have on us and how they influence our behavior. Others (Max or John Stackhouse, I believe) have argued that rather than asking WWJD, we should be asking WWJHD (i.e., what would Jesus have us do?). In other words, because Jesus lived in a different time and faced different realities, we can't always follow in Jesus' steps. Instead, we need to take his vision of what God's kingdom entails and do our best to apply it to our current situation.
Instrumental pacifism contends that pacifism is the right thing to do because it works. Adherents of this form of pacifism often point to Martin Luther King, Jr. and Ghandi as empirical proof that it does. I remember once visiting a booth at a peace fair that had a calendar where each month included an example of where the pacifist approach has worked. This form of pacifism has come under withering criticism from a number of quarters as being hopelessly naive (i.e., history shows that it doesn't always work), with Reinhold Neibuhr's (a liberal) Moral Man and Immoral Society probably being one of the more compelling. (As a side note, Neibuhr is President Obama's favorite theologian. Obama was certainly channeling Neibuhr in his Nobel Peace Prize's acceptance speech, and it helps explain why he hasn't turned out to be the "dove" that many on the left seemed to assume that he would be.)
Eschatological pacifism, associated primarily with John Howard Yoder and Stanley Hauerwas, differs from the previous two in that it's emphasis is more on the collective than the individual, and it makes no claims that it always works. It is rooted in its belief in Jesus' incarnation and resurrection. The incarnation is seen as necessary because if God is not reflected in Jesus' life, death and teachings, then there is no reason to believe that the peaceable kingdom which Jesus preached and lived reflects God's will for the world. The resurrection is deemed important because it is seen as God's vindication of Jesus' life and ministry. By raising Jesus from the dead, Christ not only became head of the church but the Lord of history, thus making God's coming nonviolent kingdom accessible for Jew and Gentile alike (The Hauerwas Reader, p. 439, 440). So central are these two beliefs to this strand of pacifism, I am certain that if Hauerwas ceased to believe in either one or both of them, he would cease to be a pacifist. A key difference between this form of pacifism and instrumental pacifism is that it doesn't believe that pacifism always "works." It will sometimes fail, and as a consequence the innocent will suffer. Nevertheless, eschatological pacifists argue that Christians should embrace pacifism because the primary calling of the Church is to be a witness to God's coming (nonviolent) kingdom. Or as Hauerwas likes to put it, the church is called to be a peaceable kingdom in the midst of a world at war. This last point highlights how this form of pacifism differs from WWJD pacifism: the latter is highly individualistic, while this one is not. WWJD pacifism is something individuals do by themselves. Eschatological pacifism is something that the church does together.
Needless to say, eschatological pacifism has come under criticism as well, the most common one being that Christians have a moral responsibility for their neighbors, that we cannot, in good faith, let them suffer if we are in a position to do something about it. A critique such as this, of course, brings us back to the just war tradition, which as I noted at the outset, I'll cover in a later post.