Fernando Tesón offers two “humanitarian rationales” for the war in Iraq. The first, which he calls the “narrow” rationale, is that the war was fought to overthrow a tyrant. The second, “grand,” rationale is that it was fought as part of a strategy for defending the United States by establishing democratic regimes in the Middle East and throughout the world–peacefully, if possible, but by force if necessary. Both rationales strain the traditional understanding of humanitarian intervention.

As the following papers demonstrate, Michael Walzer's Just and Unjust Wars continues to provoke thought and debate two decades after its publication. The book remains widely taught in college courses and is cited whenever the morality of war is discussed. It is appropriate, then, to celebrate the book's twentieth anniversary by reconsidering its arguments in light of what we have learned in the intervening years

The papers were discussed at a symposium hosted by the Carnegie Council in May 1996 and have been revised to take account of the conversation that occurred there. David Hendrickson takes issue with the book's criticism of realism, pointing to realist elements in Walzer's own argument. Theodore Koontz provides a careful analysis of some problems in Walzer's treatment of the noncombatant immunity principle. Both papers deal with the tension in Walzer's book between a morality of rights and a morality of consequences, a tension that Joseph Boyle illuminates in his contribution. And in a paper inspired by the symposium debate, Michael Joseph Smith provides an appreciation that serves as a readable introduction to the issues considered by the other contributors. Finally, Michael Walzer responds in what, if past is prologue, won't be the last word on the argument of Just and Unjust Wars.

This article discusses the moral principles underlying the idea of humanitarian intervention. The analysis is in two parts, one historical and the other philosophical. First, the article examines arguments made in late medieval and early modern Europe for using armed force to punish the violation of natural law and to defend communities from tyranny and oppression, regardless of where they occur. It seeks to understand how moralists writing before the emergence of modern international law conceived what we now call humanitarian intervention.

In the context of international law, humanitarian intervention is usually understood to be an exception to the nonintervention principle. However, the natural law tradition regards international law as less important than the moral imperative to punish wrongs and protect the innocent.

Second, the article considers how humanitarian intervention is justified within the reformulation of the natural law tradition displayed in recent efforts to theorize morality along Kantian lines. In this reformulation, humanitarian intervention is a product of the duty of beneficence and, more specifically, of the right to use force to protect the innocent. The article draws upon the biblical injunction “Thou shalt not stand idly by the blood of thy neighbor,” which has become a centerpiece of the modern reformulation, and briefly explores its application to humanitarian intervention in the context of international relations today. This reformulation of natural law explains why, despite modern efforts to make it illegal, humanitarian intervention remains, in principle, morally defensible.

Nardin uses the Eastern European experience of the late 1980s and the works of Adam Michnik and Vaclav Havel to demonstrate the traditional cosmopolitan Kantian notion of morality in the “appeal to universal human values.” Nardin uses three major elements to argue the impossibility of such a concept: “the law of nature,” based on Stoic and Judeo-Christian foundation, focusing on reason and rationality of the individual rather than custom or divine authority; the uniqueness of various cultures challenging the universal “cosmopolitan” outlook on morality; and the differences among universal principles of morality relative to personal human experiences throughout time. Nardin concludes that the moral renewal in Eastern Europe is evidence that destructive consequences of moral diversity do not preclude a civil society once agreements on authoritative principles and laws are institutionalized. Each individual's own ethical conduct and internal moral guidance offer the basis for criticism and reform of law through membership in particular communities and common humanity.

The global justice debate has largely ignored law. But that debate presupposes a legal order within which principles of justice could be implemented. Paying attention to law alters our understanding of global justice by requiring us to distinguish principles that are properly prescribed and enforced within a legal order from those that are not. Given that theories of global governance depreciate law and that cosmopolitan and confederal theories are utopian, the most promising context for a realistic global justice discourse is one that is focused on strengthening, not transcending, the international legal order.

Thinking about international affairs has oscillated between idealism and realism throughout the modern period. Moralists continue to search for a way to combine what is reasonable in each in an ethically defensible middle between those extremes. Such efforts often yield a soft version of political realism: an ethics of compromise between moral ideals and real-world interests. But this resolution fails to escape an awkward dichotomy between “morality” and “reality,” as if moral considerations were not real and interests never illusory. It also rests on a simplistic conception of politics. Politics is distinguished from other activities in being concerned with obligations prescribed and enforced within a legal order, and those who make political decisions cannot ignore these obligations. Political decision-making must therefore take account of law, which is distinct from both morality and interest. Law may have its ultimate justification in moral principle, but it provides reasons for acting that are distinct from moral reasons. This is true of law at any level, including international law. Law also has material as well as normative force as part of the world in which decisions are made. A more nuanced middle-ground ethics, then, would take account of law as making demands of its own. If we bring law into the picture, we discover limits to action that are grounded on neither morality nor interest.

Recent trends in international law scholarship recycle objections to international law advanced by an earlier generation of political and legal realists. Such objections fail to understand the place of international law in the global order. To understand that place, we must distinguish the idea of the rule of law from other understandings of law. That idea is an inherently moral one. Theories of international law that ignore the moral element in law cannot distinguish law as a constraint on power from law as an instrument of power. A Kantian theory of international law can help to recover that moral element.