Christians need some criteria, some body of thought on war, in order to make sense of and to judge their own country’s policies. Two positions on war — the war realist position and the classic pacifist position — have serious deficiencies. The war realist position makes war an intrinsic part of a nation’s culture. But even the most justifiable wars contain acts of violence towards noncombatants and tragic loss of life. All war involves evil, and should be a last resort. On the other hand, the classic pacifist position excoriates violence as a great moral evil, to be avoided at all costs. However, this is not necessarily the case. Violence in and of itself has a morally neutral character. For example, we cannot say that what a lion does to a wildebeest is morally evil, though it certainly is violent. To judge a violent action to be morally evil we need to know something about the intentions behind the action. Thus, given the extremes of war realism and pacifism, just war tradition (JWT) offers a fruitful middle ground. At its best, JWT seeks to restrain those who would jump to war too quickly, as well as to respond effectively to external threats to a people’s welfare.
 For this reason Gary Simpson’s book, War, Peace, and God, is a welcome resource on JWT. Simpson lays out in brief but concise form the major contributions to this tradition as well as a distinctively Lutheran appropriation of the tradition. As Simpson points out, it’s not an easy task to summarize JWT. The range of thought on just war over the last 2000 years is expansive, so much so that to grant too much continuity to the tradition is misleading. Given this range, Simpson’s book does an admirable job of pointing out the different historical contexts that influenced the thought of Augustine, Aquinas, Grotius, and others who helped shape the tradition.
 I must confess that I come to Simpson’s book as an ethicist steeped in the Reformed tradition, more in tune with that tradition’s view of just war than the Lutheran. I find myself wrestling with the distinctively Lutheran sections of Simpson’s book, particularly where he talks about Luther’s two kingdoms doctrine. To my mind the distinction between spiritual authority and temporal political authority in this doctrine is too neat. For Luther there are two modes of governing the world, “the spiritual, by which the Holy Spirit produces Christians and righteous people under Christ; and the temporal, which restrains the un-Christian and wicked so that — no thanks to them — they are obliged to keep still and to maintain an outward peace.” But, contrary to Luther’s claim, the work of the Holy Spirit cannot be divided so easily. It works both in church structures as well as political structures, though how and when and where it works remains a mystery.
 To see how the two kingdoms doctrine makes a difference in the way one thinks about war, consider the discussion on war that took place between H. Richard Niebuhr and his brother Reinhold Niebuhr in the early 1930s. The Niebuhrs were shaped by their membership in the Evangelical Synod of North America that drew from the Lutheran and the Reformed traditions. Both Lutheran and Reformed doctrines played a role in their thinking, but in different ways. H. Richard was fascinated by the reformed emphasis on the kingdom of God, inspired by Calvin’s doctrine of sanctification. Reinhold’s political realism was strongly shaped by Luther’s two kingdom doctrine, so that he sharply distinguished between what is possible in a fallen world and what is promised in the eschaton. Both were influenced by Christ’s self-sacrificing agape love, but whereas Reinhold argued that such love invariably leads to suffering in this world, H. Richard argued that such a conclusion too quickly closed off the possibility that God is working in history to redeem the world.
 In the spring of 1932, Reinhold and H. Richard conducted a debate over the proper response to the Japanese invasion of Manchuria. H. Richard believed that the best course of action was for individuals to reflect on their own sinfulness and to repent of that sinfulness as a way to prepare for the kingdom of God on earth. He argued that any military intervention on the United States’ part would suffer from the same hubris that was evident in the Japanese invasion. Reinhold argued that the kind of utopia his brother hoped for would never come to pass in this life and that the best we could do would be to meet force with force, with the goal to be to end the conflict as quickly and painlessly as possible.
 Reinhold’s view of history highlighted certain tragic dimensions of the reality of sin in our world. He believed that H. Richard was too sanguine about the possibility that governments and institutions could embody the will of God. He also characterized H. Richard’s position as a purely passive one: in order to avoid sin the best course of action was not to act. But the debate was more about the type of action that is appropriate for a Christian in a violent world.
 The weaknesses found in each of the Niebuhrs’ positions reflects the potential weaknesses of Lutheran and Reformed thinking on just war. Reinhold’s position too quickly rules out the possibility that the kingdom of God may penetrate the kingdom of the world, whereas H. Richard’s position risks collapsing the two into each other. An overemphasis on two kingdoms doctrine in just war thinking may shut down the prophetic voice of the church. On the other hand, a Calvinist emphasis on the kingdom of God in just war thinking may either end in holy war or, in H. Richard’s case, a pacifist quietism. We need to keep these potential pitfalls in mind in our own thinking about just war.
 Another area of concern that bears treatment has to do with our motives for going to war, even when these motives are altruistic. When one reads Augustine, Aquinas, and many of the reformers, one is struck by the emphasis they place on order. It is clear that these individuals lived in chaotic times: Augustine’s City of God was written in response to Alaric’s sack of Rome, Aquinas’ brother Rinaldo was put to death when he was caught in a power struggle between the pope and the Emperor, and the civil and religious unrest caused by the Reformation was considerable. The situation in some parts of our world today is not much better: individuals in countries with stable governments are afflicted by acts of terrorism, and those in countries with unstable governments are subject to famine and genocide. But how far may we go in our efforts to establish order in a chaotic world?
 One of the strengths of Simpson’s approach to JWT is that it recognizes the limitations of using war to establish order. Simpson employs the criteria for going to war (jus ad bellum) and for conduct in war (jus in bello) to demonstrate that these criteria are restricting criteria, used to limit war, rather than stepping stones by which a just war may be launched.
 Contrast this approach with Jean Bethke Elshtain’s position in her book, Just War against Terror. From her reading of Augustine, Elshtain concludes that it is critical for governments to use their power to establish order. Force is thus necessary in times when civic order is threatened. Elshtain believes that war can be an instrument for justice when it is used to bring about a more perfect peace. For Augustine true peace exists only in the city of God. In contrast, earthly peace is not only temporal, but partial. Therefore earthly peace must be examined critically, just as war ought to be examined critically, according to a standard of justice exemplified, but only partially revealed, in the city of God. Elshtain argues that America’s democratic principles, which ensure equal rights for all people regardless of race or creed or gender, are the closest thing the world has to a standard of ideal justice. In addition, America is in a unique position of power and has the will to use that power to promote justice abroad. She thus asserts that America holds the keys to a more just peace in failed states around the world.
 Here is where the distinction between just intention and just cause, two criteria in just war thinking, is critical. Take the situation in the Sudan. Given the accounts of rape and murder and genocide on the part of the Janjaweed militia in Sudan, should the United States intervene by sending military troops? No doubt such a venture would meet the criteria for just intention, but it would fail to meet the criterion of just cause. Just cause requires that the war be a proportionate response to an injury incurred. But in this case the injury has not taken place on US soil, so the US would be operating as a third-party acting on behalf of the injured. Such an act violates the sovereignty of the Sudanese government, which would see such a military presence as an incursion by a foreign government. Ironically, going to war for humanitarian reasons proves to be more problematic according to just war criteria than going to war to protect one’s own citizenry from harm.
 Near the end of War, Peace, and God Simpson highlights the contemporary Christian just peacemaking initiative started in 1992 by 23 Christian scholars and activists. This group proposed a list of 10 practices involved in just peacemaking that included cooperative conflict resolution and efforts to stimulate just and sustainable economic development. This ecumenical group brought together the thinking of just war churches as well as peace churches, the Protestant tradition as well as the Roman Catholic. While members of this initiative disagree on whether or not war may be necessary in certain circumstances, they do agree that the voice of the church and the efforts of the church need to be focused on establishing justice through peaceable means. As we continue to think about the violent world in which we live, we would do well to consider the practices of our own churches and the ways in which such practices support peace. It is a tribute to Simpson that in his explication of JWT he always keeps in mind the goal of just peace.
 From Luther’s Temporal Authority, LW 45:91-92, as quoted in Simpson, pages 53 — 54.
 See The Christian Century, H. Richard Niebuhr “The Grace of Doing Nothing,” March 23, 1932, 378 — 80, Reinhold Niebuhr , “Must We Do Nothing?” March 30, 1932, 415 — 417, and H. Richard Niebuhr ,“The Only Way into the Kingdom of God,” April 6, 1932, 447.
 See Jean Bethke Elshtain, The Just War Against Terror (New York: Basic Books, 2003), 166.