Must Christians be pacifists?

In a post praising Stanley Hauerwas, Will Willimon mentions among Hauerwas’s great contributions to the church his emphasis on pacifism.

Hauerwas argues in strong terms that following Jesus requires pacifism, and he has criticized Christian theologians such as Reinhold Niebuhr who make arguments on behalf of some sort of just war theory.

The United Methodist Church’s Social Principles would likely draw Hauerwas’s criticism. We deplore war, but do not rule it out, for instance here:

We deplore war and urge the peaceful settlement of all disputes among nations. From the beginning, the Christian conscience has struggled with the harsh realities of violence and war, for these evils clearly frustrate God’s loving purposes for humankind. We yearn for the day when there will be no more war and people will live together in peace and justice. Some of us believe that war, and other acts of violence, are never acceptable to Christians. We also acknowledge that many Christians believe that, when peaceful alternatives have failed, the force of arms may regretfully be preferable to unchecked aggression, tyranny and genocide.

Or here:

We believe war is incompatible with the teachings and example of Christ. We therefore reject war as an instrument of national foreign policy, to be employed only as a last resort in the prevention of such evils as genocide, brutal suppression of human rights, and unprovoked international aggression.

The founder of Methodism, John Wesley, wrote that war was a reproach to Christianity itself, a position which might make him more of a pacifist than our denomination.

 
So, in honor of Hauerwas, I am wondering how central pacifism is to Christianity. I tend to be persuaded by Reinhold Niebuhr that Christians cannot avoid all violence and war. I suppose I end up pretty close to the United Methodist position that finds war a tragic necessity at times. I’m not convinced I am correct about this, and like all Christians I long and hope for the day when we learn war no more, but I do not see that that day is upon us. Not yet.

What about you?