For several centuries, the defining framework for world order has been primarily associated with the Peace of Westphalia negotiated in 1648 at the end of the Thirty Years War, and treated as the beginning of the modern world. This modern world order, geographically deriving from the experience of Europe, was premised on the emergence of the sovereign, territorial state as the dominant political actor. This statist world order was clearly Eurocentric in its essential nature, conceiving international society on the basis of the relationships between the main European states and viewing the relationship with non-Western political communities as based on hierarchy, with the superior Western states governing subordinated non-Western states. The characteristic form for this hierarchical arrangement was based on colonial empires. The states that belonged to international society as full members during this early period were autocratic in character, mainly monarchies. It is important to understand that this state system exhibited a strong tension between a series of juridical ideas based on the equality and autonomy of states and the realities of power that reflected inequalities. World order as an analytic concept encompassed both the legal domain of equality and the geopolitical domain of inequality. The state system evolved largely through tests of power associated with the major states as war was considered a discretionary instrument of a sovereign state. Indeed, war served a legislative function as there was no reliable peaceful means to achieve adjustments that were needed in view of changing power balances and differing policy priorities. International law emerged over time as a means by which states could stabilize cooperative aspects of international relations such as the exchange of diplomats, maritime safety, communications, and transportation. It also served to legitimate the dominance and exploitation of the weak by the strong through a variety of doctrines and practices that justified intervention, including the broad notion of ‘humanitarian intervention’ used by European powers to protect Christian minorities supposedly jeopardized by the Ottoman Empire or the Western Hemisphere claims posited by the United States by way of the Monroe Doctrine (1823) that came over time to authorize a wide range of interventionary moves. In this period leading up to the twentieth century there was no attempt to limit by international law recourse to war as an instrument of national policy or even to regulate its conduct. There was, to be sure, widely endorse ethical ideas associated with the just war doctrine and natural rights thinking that cast moral doubts on aggressive behavior, especially if directed at other European states. These ideas were carried over to some extent to customary international law, establishing some legal norms that could be brought to bear against certain unrestrained forms of war making. Among the more influential of these ideas were those insisting that uses of force against another state should be governed by considerations of proportionality (as between the quantum of force used and that needed to rectify the alleged grievance); discrimination (the use of force must be restricted to military targets) necessity (that only force needed to achieve belligerent goals would be used); and humanity (that care be taken to avoid cruel or superfluous suffering as in the treatment of the wounded or prisoners of war). As the decision to use force was unregulated by international law, it was only the prudence and self-restraint of major states, as well as their strategic alliances, that sustained the security and political independence of smaller and weaker states. The formal protocols of the Westphalian form of world order did give rise to norms of mutual respect for territorial sovereignty, but the geopolitical protocols of power paid little attention to such restraints. A realist calculus came to dominate world order practice, as best theorized by Machiavelli, Hobbes, and Clausewitz all of whom disregarded purported ethical and legal constraints on the external exercise of power by sovereign states. The American Revolution, and particularly the French Revolution, shifted the world order focus to internal state/society relations, and ended the autocratic traditions of monarchy that had dominated domestic politics in the early centuries of the Westphalian era. The main result, and stake, of the American Revolution was political independence from the British Empire, an initial legitimation of anti-colonial wars of emancipation. This struggle for political and economic independence was followed by the emergence of democracy, proclaimed in its distinctive American, republican form. But for France, it was a matter of ending, at least temporarily, royal rule, and proclaiming liberty, equality, and fraternity as ‘the rights of man’ (now ‘humans’), being the necessary foundation of a legitimate state, not only for France, but for any sovereign political community. It was this French idea of rights, also embodied in the American Declaration of Independence, that laid the foundation for the ethos of self-determination, which was not set forth explicitly until more than a century later. Throughout the nineteenth century, the interventionary implications of the French Revolution receded, and the primacy of territorial sovereignty was reaffirmed in the law and diplomacy of the full members of international society. Thus international trade in slaves might be prohibited, but the practice of slavery was considered a matter of domestic policy, to be respected by anti-slave states. But in relations between the Eurocentric core (that included the United States) and the non-Western periphery, interventionary behavior was justified either as ‘white man’s burden’ or as ‘diplomatic protection’ of overseas interests. In other words, world order continued to be based on the interplay of states in the core, while the core states projected their power in ways that encroached on most other political communities. Some classic empires managed to maintain varying degrees of autonomy, most notably the Ottoman Empire and China, although both were badly penetrated by European powers, as well as by the United States. It was in the setting of World War I that world order began to shift in new directions. On the basis of the new primacy of the United States as a decisive force in the defeat of Germany in World War I, the American leader, Woodrow Wilson, became convinced that realism was responsible for useless carnage, and that a better way had to be found to deal with relations among sovereign states. For Wilson this meant the outlawry of war, and the establishment of an international organization tasked with keeping world peace. Wilson’s vision of collective security was diluted by realists at home and in Europe, and what emerged was a toothless League of Nations that nurtured delusions of a warless world, but lacked the means to challenge aggressor states. The will to do away with war had not then, and has not yet, reached nearly the stage that the reformist resolve to end the international slave trade had achieved by the early nineteenth century. Somewhat more progress has been achieved, but haltingly and inconsistently, with respected to mitigating the cruelty of war, its methods and tactics, by way of a widely upon framework for international humanitarian law. Wilson also launched the idea of self-determination in this same period of seeming international fluidity after World War I. Wilson had the collapsing Ottoman Empire in mind, and had no intention to set forth a radical principle of self-determination that could, if implemented, undermine the established world order that included the overseas colonial empires of the European powers. Despite the obvious implications for oppressed and exploited peoples throughout the world, Wilson did not regard his proclaimed support for self-determination as grounds for the repudiation of colonialism. Yet, as seems inevitable in retrospect, others quickly applied the idea of self-determination to their own circumstances. Lenin, particularly, saw the main sphere of application for self-determination to be in the colonized countries of the non-Western world. After all, the Soviet Union had no colonies to lose, and it fit Communist ideology to affirm the struggle of the oppressed and exploited. The genie of self-determination had permanently escaped from its confinement, but there were formidable forces at work to limit the damage. The colonial powers fought hard to maintain their empires, and there was reluctance by the United States to support what came to be called Third World Nationalism because of its strategic and civilizational identifications with the Eurocentric core. At the same time, the Soviet Union turned inward, and concentrated on the rivalry between European powers that eventuated in World War II. On the other side of the global policy agenda, the normative ideas generated by the French Revolution were eclipsed by the intensity of nationalist identities, and the ties between peoples and states. This feature of world order was most prominently raised by the rise of Nazism, and the subsequent Holocaust directed against Jews and others. It was evident that even the liberal democracies were not prepared to intervene protectively to prevent abuse even of such an extreme character. In this sense, self-determination, to the extent that it was expressive of world order, became aligned with principles of non-intervention rather than with humanistic ideas of solidarity, intervening to secure the rights of persons and peoples. World War II brought several prior attributes of world order into renewed contention. The United Nations Charter, reviving the failed efforts of the League of Nations, made a determined assault on the right of a state to wage discretionary wars. This revival was coupled with treating German and Japanese leaders who were viewed as responsible for initiating World War II as ‘war criminals,’ at the Nuremberg and Tokyo war crimes tribunals. It was also reinforced by the widespread perception that future wars would be a human catastrophe without winners and losers, a view that gained credibility due to the incredible destructive harm done by the atomic bombs dropped on Hiroshima and Nagasaki in 1945. Although the United Nations Charter prohibited all uses of force except in cases of strict self-defense, it also granted the five permanent members of the Security Council a veto power that effectively exempted them from accountability to these restrictive UN guidelines. Also, the prohibition of force was supposed to be coordinated with the establishment of a functioning mechanism of collective security administered by the Security Council. This mechanism was never activated. As a result, states have argued that their right of self-defense can be exercised on the basis of their shifting security interests regardless of what the textual language of the UN Charter seems to require. As with the League, the impulse to outlaw and criminalize aggressive war ends up with a half-hearted gesture as the political will is lacking in the main states to transfer the needed authority and capabilities to an international institution. The Westphalian approach to war among major states holds, which rests on ideas of deterrence and prudence. Given the apocalyptic character of nuclear weaponry, and the increasing costs of warfare, there are many reasons for political leaders to avoid large-scale wars of the traditional kind involving sovereign states. It would be a mistaken perception to suppose that states are never under any conditions prepared to give up their sovereign prerogatives. For instance, major governments have pushed hard to create regional and global trading regimes that require reliance on international procedures and regimes that have the authority to override national lawmaking processes. This dynamic of internationalization is perhaps most ambitiously evident in some of the arrangements associated with the European Union. It is also manifest in relation to the operations of the International Monetary Fund, World Bank, and especially the World Trade Organization. The latter has far reaching dispute settlement authority that can impinge very significantly on the domain of national autonomy with respect to economic policy. It is with respect to the war/peace subject-matter, and related issues of accountability of leaders, that the strict Westphalian logic of sovereignty remains most descriptive of world order. World War II did have the effect of greatly weakening the colonial powers of Europe. In this sense it created opportunities for several varieties of Third World nationalism to push forward their claims, and push they did. With the two now dominant states, the United States and the Soviet Union not being colonial powers in the accepted sense, the geopolitical climate turned became less and less favorable to colonialism and more and more sympathetic nationalist tendencies and an affirmed right of self-determination.