This chapter begins with a brief overview of important developments before the birth of the UN and over the UN’s lifetime as a prelude to a discussion of the five gaps. It then explores the recent emphasis on prevention rather than reaction and the contribution by two international commissions. A concluding section discusses the multiple layers of actors and actions needed for the contemporary global governance of the use of force.

Establishing the UN was a small but symbolically crucial step in taming the use of force as a means of settling quarrels among different members of the human family scattered across the globe. Violence is endemic in human relations at all levels of social organization. War between states has been a feature of the current international system since its inception in 1648, following the Peace of Westphalia. But military aggression is an affront to international norms regarding peace and security.

War has traditionally performed certain functions in international relations from three points of view. From the perspective of states, it has served as an instrument of policy, a means to a desired end. Thus, in Vietnam during the 1960s, the opposing sides shared one belief: that war was the most effective instrument for solving the dispute. From the perspective of the international system, war has determined the shape of the international order. It has been the arbiter of the creation, survival, and elimination of actors in the system; of the ebb and flow of political frontiers; and of the rise and decline of regimes. From the viewpoint of international society, war is both a manifestation of disorder that threatens the survival of the society and an instrument to enforce community values and goals. In the first sense, war is dysfunctional; in the second sense, it is the functional equivalent of a municipal police force.

The problem of peace and order is not new. At the Congress of Vienna in 1814, major European powers established the Concert of Europe system, transforming a military alliance for the single purpose of defeating Napoleon into a longer-term loose political organization whose goal was to prevent one power from dominating Europe. The Concert of Europe was an innovative attempt to construct new machinery to maintain the peace among the great powers.

The Hague Conferences of 1899 and 1907 signaled the broadening of international relations, in terms of both the number of participants and the international agenda. They both pointed to an emergent extra-European international system in which the lesser powers would demand a say. In addition, with their emphasis upon mediation, conciliation, and inquiry, the conferences demonstrated a rationalistic and legalistic approach to international disputes.

The outbreak of world war in 1914 and 1939 discredited the old balance-of-power system that relied on the central role of the great powers. The two major international organizations of the twentieth century were created after world wars. People who were horrified by the destructiveness of modern war created the League of Nations and the United Nations to avoid a repetition of such catastrophes.

By signing the League Covenant, member states signified their “acceptance of obligations not to resort to war” (Preamble). To that end, they agreed to submit disputes to arbitration or judicial settlement and to refrain from going to war until three months after arbitration or adjudication (Article 12).

The League was prepared to condemn Japanese aggression in Manchuria in 1931, a significant normative advance even though there was no prospect for any collective action. The Italian invasion of Ethiopia in 1935 presented the League with its moment of greatest triumph: for the first time, the international community of states, acting through institutionalized channels, condemned aggression, identified the aggressor, and imposed sanctions. For the first time, the ideal that the international community of states can take joint coercive measures against outlaws was advanced. However, Ethiopia stands as the symbol of the League’s failure to realize these high hopes because Italy secured its ends through the means of its choice—forceful military occupation.

An important step in the development of the idea that an international community has both the right and a responsibility to prevent armed conflict between its member states was the Pact of Paris of 1928 (also known as the Kellogg-Briand Pact), in which signatories condemned “recourse to war for the solution of international controversies, and renounce[d] it, as an instrument of national policy in relations with one another.”⁴ The facts that the pact was not enforceable and that the signatories insisted on qualifications—for example, the extension of self-defense to include a state’s colonies—eroded the practical significance of the agreement. Yet the declaration of principle, that war was henceforth to be treated as an illegitimate method of dispute settlement, was of symbolic significance even if it fell well short of being a contractual obligation.⁵

Although the League of Nations failed to prevent another world war in 1939, the UN resurrected the cause of securing peace from the ashes of World War II. The fact that the UN was closely modeled on the League was testimony to the fact that while the League had failed, people still had faith in the idea of an umbrella international organization to oversee world peace and cooperation. U.S. president Abraham Lincoln spoke of the “scourge of war,”⁶ an apt description that found its way into the UN Charter, the Preamble of which begins with the clarion call: “We the peoples of the United Nations determined to save succeeding generations from the scourge of war, which twice in our lifetime has brought untold sorrow to mankind.”

The UN seeks to replace the balance of power with a community of power and represents the dream of a world governed by reason and the rule of law. The UN vision replaced the League’s efforts to abolish war with a Charter that included a provision that states could use military force collectively. The intention was that negotiations and the rule of law would replace the unilateral use of force and that collective security would guarantee the sovereignty and territorial integrity of all states. The Charter invested the Security Council with the authority to authorize military action to restore the peace, and only when the Security Council failed to act were individual countries allowed to use force in self-defense.

Thus, collective decision making was the means of outlawing war and mobilizing the international community of states to deter, apprehend, and punish international lawbreakers. Especially significant were the Charter provisions that outlawed the use of force in Article 2 (4) unless it was authorized by the Security Council and that outlawed the use of force except in self-defense as spelled out in Articles 39–51. A cynic will be quick to indicate that this article is breached as frequently as it is respected, but the creation of a legal basis for calling miscreants (other than the five permanent members and their close allies) to task is a step forward.

However, the persistent reality of numerous interstate, transregional, and internal armed conflicts; the frequent collapse of peace agreements and relapse into armed conflict; and the continual rise of fresh conflicts discourages pacifists and conflict managers. While the Charter’s version of collective security has never been realized—with the possible exceptions of actions taken during the Korean War and the 1991 Gulf War—and the autonomous forces required to keep the peace have not materialized, nonetheless the United Nations has made important contributions. Unarmed UN military observers and lightly armed UN peacekeepers have made a difference since their first deployment in the 1948 Middle East War and the 1956 Suez crisis, respectively. Both continue to maintain the peace in conflict-ridden parts of the globe where neutral and impartial armed forces are required. The UN has continued to adapt peace operations to include important multifunctional duties, from monitoring elections to humanitarian action. In short, the absence of a world military force to ensure the peace has not meant that elements of global governance are not present.

One more antecedent is critical for an understanding of the intellectual history of the United Nations with respect to warfare. The organization’s single most important and consequential member is the United States, and its single most important and influential group is the European Union. The political culture of the respective attitudes of these two entities toward warfare, which have been conditioned by sharply contrasting historical experiences and collective memories, is a source of occasional friction in UN diplomatic circles. While other major twentieth-century combatant states suffered heavy military and civilian casualties, American military casualties were surprisingly light and its civilian deaths negligible. While Britain, France, and Germany lost between 1 and 2 million soldiers each in World War I, the United States lost fewer than 120,000. While China, France, Germany, and the Soviet Union lost between 2 and 11 million soldiers in World War II, only about 420,000 U.S. soldiers died. The total U.S. civilian deaths from the two world wars combined was less than 2,000, compared to the deaths of half a million Yugoslavs and between 2 and 16 million Germans, Poles, residents of the Soviet Union, and Chinese.⁷ Robert J. Rummel estimates that 217 million lives have been lost in wars, pogroms, genocides, and mass murders during the twentieth century.⁸ And of course this figure does not include the many more uncounted who have lived diminished lives as refugees, internally displaced persons, detainees, widows and widowers, orphans, and paupers.⁹

The human and collective national toll of these cold statistics is worth a moment’s reflection. For victors and defeated alike in Europe, wars meant displacement, destruction, deprivation, privation, invasion, occupation, and mass murder. Europeans have a shared memory of war as a terrible human-made calamity. Would France really want to repeat its “victories” in the two world wars? Moreover, most countries were increasingly militarized during the two world wars and their sense of society and community badly fractured, as Tony Judt tells us: “States and societies seized . . . by Hitler or Stalin . . . experienced not just occupation and exploitation but degradation and corrosion of the laws and norms of civil society. . . . Far from guaranteeing security, the state itself became the leading source of insecurity.” That is, he continues, “War—total war—has been the crucial antecedent condition for mass criminality in the modern era.”¹⁰

By contrast, the United States today “is the only advanced democracy where public figures glorify and exalt the military.”¹¹ This partially explains the dramatically contrasting moods of triumphalism in the United States and relief in Western Europe at the end of the Cold War. And it is at least a partial explanation for the UN’s failures to bring human warfare to an end. Its most powerful member state, which has virtual control over many security issues, believes in the efficacy and morality of the use of force while rejecting that same logic when others use it.

Armed conflict is as old as the human race. How can there still be holes in our knowledge about it? By knowledge gap we mean either one or both of two interrelated shortfalls: gaps in the empirical base of facts and in the linkages between events and decisions (correlations), on the one hand; and gaps in understandings of the causes and consequences of armed conflict, on the other. Both types of gaps characterize our ignorance about war and peace.

Not everyone agrees about what constitutes war, a war casualty, aggression, self-defense, preemption, preventive war, terrorism, hot pursuit, and war crimes. Was Israel’s 2006 war against Lebanon waged in self-defense in response to an unprovoked attack by Hezbollah? Was it a preplanned escalation waiting for an opportune moment? Was it a war of aggression because the scale was far out of proportion to Hezbollah’s provocation?¹²

Even statistical methodology is highly disputed. How can one get an accurate assessment of the total casualties in Iraq since 2003? Should “excess deaths” form part of the casualty count under the catchall phrase “conflict-related” deaths? When an independent, non-UN team carried out a survey in Iraq after the 2003 invasion to determine the total casualty figure through the standard methodology of “excess deaths” (as opposed to deaths that were the direct result of fighting) and published the results in the respected medical journal The Lancet, London and Washington severely criticized the findings.¹³ The media then either stopped using these figures or qualified them by describing them as controversial. Yet the media reported a comparable study in January 2006—also published in The Lancet—that estimated the total death toll in the eight years of war in the Democratic Republic of the Congo as 3.9 million (currently the figure is 5.5 million...