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The authors of the Versailles peace conference in 1919 had great hopes for international justice. Four years of devastation gave a unique impetus to crystallize earlier aspirations and embark on new projects that would both guarantee peace and entrench justice. But what exactly was the connection between the two? How is international justice supposed to be conducive to peace? And what has become of that vision today?

Today’s International Court of Justice and the Permanent Court of Arbitration sit in Andrew Carnegie’s Peace Palace in The Hague, Netherlands. Andrew Dickson, in his plea to Carnegie to finance the building of the palace, insisted that it would be “a temple of peace” that would “throw open its doors for the peaceful settlement of differences between peoples.”1

Frédéric Mégret
Frédéric Mégret is a full professor and Dawson Scholar at the Faculty of Law, McGill University.

Yet the association between the two concepts is more fraught than this neat conjunction would suggest. The allure of international justice today is still partly that it is not only justice for justice’s sake—always a limited proposition in a world of distrusting sovereign states—but a means to a broader peaceful end. By the same token, some would rather sacrifice peace than abandon justice, denouncing a peace obtained through injustice as a shallow and precarious one. At what cost should justice or peace be pursued?

Three Views of Justice and Peace at Versailles

Understanding the Versailles conference can help better understand these dilemmas. At least three concepts of international justice as an instrument of peace were visible on that occasion. None of them turned out to be very successful. First, the architects of the Versailles Treaty decided that international justice could be a component of peacemaking after war. The plan to prosecute war criminals, including the kaiser himself, for “a supreme offence against international morality and the sanctity of treaties” and the “war guilt clause” were part of a movement to punish the initiators of war and excessive violence within it.2 Efforts to prosecute the kaiser, however, came to nothing after he fled to the Netherlands, which then refused to extradite him. The attempt to impose onerous reparation obligations on Germany infamously failed and is often credited as a cause of the rise of Nazism.

Second, international justice could also be part of a more forward-looking, preventative drive to rely on adjudication to avoid war. The Permanent Court of International Justice (PCIJ) in The Hague, a court designed to decide disputes between states, was very much conceived as part of the emerging League of Nations project of collective security. It harked back to the 1899 Hague Conference, which had led to the adoption of the Convention for the Pacific Settlement of International Disputes and the creation of the Permanent Court of Arbitration. The gist of international adjudication was that it would provide a mode of pacific resolution of disputes. If states went to arbitration or submitted their disagreements to international courts, so the reasoning went, they would not go to war.

The PCIJ was rendered fragile from the start, however, by the fact that submission of disputes to it was not compulsory and was in fact, when it came to matters of national life and death, quite unlikely. The court’s fortunes thus tended to follow the ebb and flow of international relations—a system to manage peace rather than to impose it. It was most successful in the relatively peaceful 1920s, but states largely ignored it during the treacherous 1930s. Whatever small contribution the court may have made to international peace was completely obscured by the Second World War—indeed, quite literally so, as the invasion of the Netherlands by Germany made it impossible for the court to convene.

Finally, the Versailles Treaty, with its emphasis on disarmament and the banning of secret treaties, could also be seen as a manifestation of a deeper pacifist ethos. Today, pacifism is often reduced to a nonviolent agenda of wholesale opposition to war, including a refusal by some to participate in military action (even in self-defense). But the pacifist tradition is arguably far richer and encompasses a wide spectrum of initiatives to educate for peace, deflate aggression, exercise democratic control over foreign policy, combat militarism, disarm, or mediate.

In the midst of the First World War in 1915, for example, the Woman’s Peace Party improbably proposed a process of continuous mediation between warring parties. Contra a tendency to emphasize responsibilities for conflict, the 1915 International Congress of Women organized in The Hague insisted on the sheer cruelty of war. The International Committee of Women for Permanent Peace sought to intervene with all parties to convince them to withdraw from the conflict. It eventually took a stance against the Versailles Treaty, arguing that the treaty’s harsh punitive stance would only lead to renewed hostilities.

These three ways of imagining justice’s contribution to peace still resonate a century on, despite the limitations and failures of Versailles (for more, see the essay by Jay Winter in this volume). But they also come to us as the faint and distorted echo of a world that is quite different from ours, and that has, in the meantime, significantly reframed the dilemmas of international peace and justice.

Nuremberg’s (Brief) Turn to International Law

The Second World War saw the wholesale violation of treaties and the trampling of states’ sovereignty, which the PCIJ had vainly sought to uphold. The victors of 1945 envisaged a much more robust system of collective security but gave no obvious place in it to instruments of international justice. This is not to say that the International Court of Justice (ICJ), founded in 1945, could not be conducive to peace, but nor did it give any particular pride of place to avoiding war. Instead, the United Nations (UN) Security Council emerged at the apex of the new system of international peace and security.

For a time, the Nuremberg and Tokyo tribunals of 1945 and 1946 captivated the world’s attention and seemed to herald a renewed role for international justice. In contrast to 1919, they suggested that simply extracting massive reparations from the defeated was no longer a viable or desirable option, and that the international community should hold individuals directly accountable for their crimes, even though they had operated on behalf of states. These postwar tribunals, for all their flaws, convicted dozens of defendants for their crimes.

Aerial view of the Peace Palace, The Hague. (Library of Congress)

The notion of “crimes against peace” was central to this process. The idea was based on the bold assertion that war had been made illegal and even criminal by the Kellogg-Briand Pact of 1928 (Nicholas Butler, president of the Carnegie Endowment for International Peace from 1925 to 1945, won a Nobel Peace Prize for promoting the agreement). This recast peace not simply as a desirable state to be reached through patient and voluntary arbitration or collective security, but as something to be protected through the criminalization of its breach. The problem of peace became a problem of international law enforcement. The International Law Commission would go on to codify crimes against peace as part of customary international law. The UN Charter itself prohibited the use of force by states against each other. The prohibition of the use of force in international relations received enthusiastic backing from newly decolonized nations, who saw its importance in upholding their sovereignty.

Yet this seemingly momentous breakthrough failed to dramatically alter international reality or reinforce the place of international justice in the collective security regime. The Security Council remained the crucial vehicle for collective security and resisted efforts to be regarded as a law enforcement body. As submission of disputes to the ICJ was not compulsory, it almost never heard cases involving international violence and perceived life-or-death decisions. Before long, Nuremberg and Tokyo looked like isolated episodes rather than the prototypes for international justice they had been briefly imagined to be. With the advent of the Cold War, the International Law Commission soon suspended its work on a draft Statute for an International Criminal Court—and would only resume it some four decades later.

The End of the Cold War and the Ambiguous Promise of Justice

The end of the Cold War opened up new possibilities at the intersection of international peacemaking and international justice. A unified Security Council responded with force to Iraq’s invasion of Kuwait. In these early years, some were even ready to see the council as the enforcement arm of international law. The ad hoc international criminal tribunals for the former Yugoslavia (ICTY) and Rwanda (ICTR) were specifically created by the Security Council as measures to reestablish international peace and security. This raised the hope that justice could indeed be deeply conducive to peace, vindicating the early enthusiasm of civil society activists that there could be “no peace without justice.”

For a while, international criminal justice even seemed to displace peacekeeping as the council’s preferred tool for intervention in conflicts. Initiatives in Cambodia, East Timor, Kosovo, Lebanon, and Sierra Leone further cemented its role as a tool to rebuild the rule of law, help mend societies, and ensure order. However, this was also a very selective form of justice. It needed to either be triggered by the council, with the consent of the permanent members, or to be agreed to by the states involved.

In 1998, the Rome Statute was adopted and, in 2002, the long-awaited International Criminal Court (ICC) came into being. The ICC also sits in The Hague, barely a mile from the Permanent Court of Arbitration and the International Court of Justice, but a world away in terms of its jurisdiction and mode of operation. Unlike the previous international criminal tribunals, this was meant to be a permanent body with jurisdiction potentially over all acts of genocide, crimes against humanity, war crimes, and even aggression committed on the territory or by the nationals of one of its more than 100 states parties. Its preamble specifically recognized that “grave crimes threaten the peace, security and well-being of the world.”3

The Rome Statute contains an important provision explicitly making it possible for the Security Council to refer “situations” to the court on the basis of Chapter VII of the UN Charter. This provision suggests a rather instrumental vision of justice in which tribunals operate at the behest but also, therefore, at the discretion of security institutions. Indeed, the Security Council’s interest in its own tribunals has waxed and waned, depending on the priorities of the moment. The Security Council referred the Darfur and Libyan “situations” to the ICC, yet the council did not always consistently back the prosecutor’s subsequent efforts.

Moreover, just as the Security Council could trigger international criminal justice, it could also rein it in by suspending the court’s investigations for six months at a time, as per the Rome Statute. This is not an entirely discretionary power and theoretically has to be exercised in conformity with the UN Charter. But soon enough it was abused, as the United States insisted that the council adopt a series of resolutions ensuring that nationals of states that are not parties (including, of course, Americans) would not be prosecuted by the court, under the threat of defunding some of the UN’s peacekeeping activities. The United States explicitly argued that ICC prosecution of nationals of nonstate parties would endanger international peace and security. The connection to peace thus proved both a boon and a curse for international justice.

A Focus on Atrocities

If at Nuremberg there had been a dominant focus on “crimes against peace,” the new tribunals had a different set of priorities. After Nuremberg, international lawyers did painstaking work to define the crime of aggression. Their efforts somewhat paid off in the 1970s with the adoption of UN General Assembly Resolution 3314, considered by many to crystallize customary international law on the subject. Yet aggression did not make a comeback as the crime at the heart of the statutes of the international criminal tribunals. Neither the ICTY nor the ICTR had jurisdiction over aggression. Even the special Iraqi tribunal missed a striking opportunity to prosecute Saddam Hussein for aggression following his attacks on Iran and Kuwait. As for the ICC, its aggression jurisdiction is still largely more theoretical than real and will only apply to the few state parties who have ratified the relevant amendments. Despite the entrenchment of international criminal justice, the nominal trend to criminalize war in the name of peacemaking has thus had much less of an impact than may have been expected.

Why the downgrading of the crime of aggression? There are least two reasons. The first is a focus on “atrocity crimes,” such as genocide, crimes against humanity, or war crimes. The peculiar character of gravity of these crimes results not from how they have imperiled peace as such (although they may also do or be a result of that) but in how they have offended fundamental humanitarian values, typically through the large-scale killing of the innocent. Crimes against peace may well have once been described by the Nuremberg tribunal as “the crime of crimes”; in more recent years, that epithet has instead been bestowed on genocide, the word first coined by Raphael Lemkin in his book Axis Rule in Occupied Europe (published by the Carnegie Endowment for International Peace in 1944).

Giving primacy to a humanitarian approach by focusing on atrocities honors the fundamental intuition that wars of aggression are primarily wrong because of their human consequences; yet it also depoliticizes the use of violence and implies a relative neutrality toward offenses against peace. After all, humanitarian breaches committed in war are crimes, whether those committing them are aggressors or acting in self-defense. Violations of international law in war (the so-called jus in bello) are seen to matter more than the breach of peace itself (the jus ad bellum). What is more, a use of force that is not in self-defense or authorized by the Security Council is sometimes claimed to be redeemable if its intent is to save civilian lives in dire circumstances. The reemergence of the notion of humanitarian intervention in Kosovo and the subsequent attempt to codify it under the Responsibility to Protect (R2P) has not laid to rest concerns that humanitarian noblesse oblige can be used to carve a loophole into the UN Charter and, effectively, endanger peace.

A second related change in thinking on aggression derives from the perception that the nature of peace itself has changed fundamentally, from a condition that characterizes the relations between states to one related to the stability and order within a state. From Somalia to Syria, the Security Council is largely responsible for this trend toward the domestication of international peace and security, which, in turn, has propelled shifts in the focus of international justice away from crimes committed by one state against another and toward crimes committed by states against their own populations or by rebel groups. The focus of both peace efforts and international justice has, as a result, fundamentally switched to the domestic sphere. This has significantly confused what it means to search for peace, although it may simultaneously have provided distinct overtures for international justice.

A New Role for International Justice?

These evolutions have potentially fundamentally changed the role of international justice from being a linchpin of a collective security system to being one technique among many to manage the world’s internecine conflicts. In the old, grandiose conception, justice was supposed to prevent war between states. In the new, more managerial conception, justice is one element of a multifaceted policy intervention within states. Justice is instrumentalized on the grounds that it will make bad actors accountable, promote reconciliation, deliver truth, or assuage victims. International justice is also increasingly seen as a force that will shape peace agreements, for example by ruling out amnesties or insisting that victims of war receive certain reparations. This more instrumental use of international justice has helped give birth to the pragmatic paradigm of “transitional justice,” a catch-all for a variety of interventions in protracted crises that often prioritizes dealing with the past as a tool of conflict resolution.

This changed approach to global conflict resolution still leaves space for international justice as a peacemaking instrument, but it raises daunting challenges. International justice remains ill at ease with purely domestic breaches of the peace—what might be termed the domestic equivalent of aggression. Its natural realm, when it comes to peace, is that of violence between states, relatively identifiable cases of aggression, and the possibility of intermediation between sovereigns. But who will bring a case against a state that has attacked its population or, for that matter, against a rebel or terrorist group that has attacked a population and/or the state? Proposals to try those responsible for the September 11 attacks before an international tribunal, for example, led nowhere (and would, at any rate, have been for quite specific terrorist offenses). Moreover, there is still no domestic equivalent of the crime of aggression. Meanwhile, other dangers continue to lurk. One concern in this context is that the more domestic the peace project becomes, the less specific it will be, becoming virtually indistinguishable from a host of activities to prop up the state. Another is that the more justice is instrumentalized, the more unrecognizable it may become to its proponents.

Justice Against Peace?

In this new context, it becomes conceivable that international justice may occasionally endanger peace. First, a tension exists between international criminal justice’s supposedly imperative character (“justice must be done!”) and the dangers that an effort to deliver justice during or after a conflict may backfire. Should justice be obtained at the cost of a renewal of hostilities—“let justice be done, though the world perish”? Conversely, should one be ready to turn a blind eye to the commission of war crimes or the very launching of hostilities so as to get parties to sit at a negotiating table? The pendulum has swung back and forth on these dilemmas.

For much of the history of international law, the default stance was that one should let bygones be bygones, and that to push too hard for accountability would contradict the effort to achieve peace through diplomatic negotiation and balancing of power. The Westphalia Treaty of 1648, which many see as the origin of the nation-state system, contained a resounding amnesty clause for all crimes committed during the Thirty Years’ War. The increased emphasis on war crimes has, by contrast, provided justice with a bigger platform, strengthening the status of accountability in peace settlements. This may lead to at least two potentially problematic consequences. First, one-time supporters of accountability may find it very difficult to climb down from a position of wholesale condemnation when it comes to negotiating with leading but tainted figures in a conflict. Second, those targeted by arrest warrants may be tempted to pursue a scorched-earth policy or to cling to power at all costs. Even if international criminal justice deters in the long run, then, it may not do so in the short term. Omar al-Bashir, for example, responded to calls for his arrest by expelling civil society organizations from Sudan.

There are ways in which the dosage of international criminal justice can be adjusted to account for conflict-resolution dynamics. According to the idea of complementarity, the ICC only has jurisdiction if a case is not being dealt with domestically. In weighing complementarity when launching an investigation, the prosecutor is required to take into account the “interests of justice.” A peace-minded prosecutor will likely tread carefully in cases where too forceful a judicial intervention might disrupt peacemaking efforts. This has happened before. For example, Carla del Ponte, then prosecutor of the ICTY, famously kept the indictment of Serbia’s Slobodan Milošević under wraps long enough that he could participate in the Dayton peace talks and sign a peace deal. But the authority of an international tribunal to make these complex decisions remains shaky, especially when dealing with sovereign and democratic states.

On occasion, moreover, it is conceivable that international criminal justice may unwittingly reinforce demands for the use of force, with potentially devastating effects for the regime of collective security. For example, the perception that Serbian forces were poised to commit genocide in 1999 in Kosovo justified what is seen by many as a major violation of the UN Charter, albeit one that may have been redeemed by its goal. The authorization by the Security Council to use “all necessary means” to protect civilian populations in Libya in 2011 soon led to regime change assisted by NATO bombings, much to China’s and Russia’s dismay. In this respect, the international justice project may have come full circle, changing from a mechanism initially designed to allow parties to settle their disputes rather than go to war, to one that targets opprobrium and sometimes authorizes violence against select parties.

Reimagining the Peace Through Law Project?

The relationship of international justice to peace remains inevitably fraught, as both are susceptible to political trends. Even in a world that is now equipped with international criminal justice institutions, the management of peace still tends to fall back on well-tried political approaches. The Security Council continues to have a monopoly on responses to breaches or threats to international peace and security, most notably through peacekeeping, but it is prone to react haphazardly to them, depending to the vagaries of power politics. This can have significant consequences on the perceived impartiality of international justice. Given these constraints, is it still possible to reenergize the project of international peace through law in the twenty-first century? Doing so may well involve returning to the project’s sources and engaging anew with its founding dilemmas.

A first avenue for progress entails reimagining what peace really is. It should be quite clear by now that the single-minded focus on interstate war always reflected a narrow, Westphalian agenda; but it is not clear that focusing on non-international armed conflict changes this fundamentally. This approach may merely reproduce an emphasis on tackling military violence as the core concern. Feminists have long emphasized, by contrast, the persistence of private violence even beyond the public sphere. What may be needed is a rethink of the pacifist agenda to deal much more broadly with the problem of violence in international relations in all its dimensions. This could mean fresh attention on the iniquities of the arms trade, the growing security response to migration, the gendered dimensions of militarism, global inequalities, or climate change.

A second area in which international justice still sustains peace is a rather old one, which would be familiar to the peacemakers of a century ago: the continued operation of conventional state-to-state arbitration and adjudication. The rise of international criminal justice, it is worth stressing, has not supplanted a more horizontal approach to dispute settlement that remains quite tied to the ideal of peace through law. The old ambition to arbitrate international legal disputes as a way of avoiding them degenerating into war, or even of adjudicating claims dealing with the use of force, has witnessed quite a comeback over the last three decades, with many cases brought alleging the illegal use of force following the ICJ’s landmark Nicaragua v. United States judgment of 1986. Moreover, the ICJ has heard and, in some cases, decided on a number of issues that implicate the broader peace project, including a series of cases on nuclear weapons or the Genocide Convention.

A third area that potentially strongly connects notions of peace and justice is human rights. Human rights protection has been a fundamental issue in the postwar era, but agendas of human rights and peace do not always fully overlap. Indeed, leading human rights organizations such as Human Rights Watch have often found themselves being perhaps exceedingly cautious about denouncing aggression. They have preferred instead to monitor humanitarian performance by diverse parties without prejudging the legality of their fighting in the first place.

Yet there is arguably such a thing as a human right to peace, part of the right “to a social and international order in which the rights and freedoms set forth by the [Universal Declaration of Human Rights] can be fully realized”4—a sort of precedent to their enjoying all other rights. Much was made in the 1970s of this idea, and it could be resurrected to challenge a view of international justice as resigned to managing conflicts rather than fundamentally problematizing violence.

All of this points to a residual impulse to imagine a different international law, one less committed to managing international security and more devoted to disrupting violence in all its forms. Whether international justice institutions can embody that aspiration or, at least, champion it remains an open question.


1 Letter from Andrew Dickson White to Andrew Carnegie, August 5, 1902.

2 Rens Steenhard, “A Supreme Offence Against International Morality and the Sanctity of Treaties: William II of Hohenzollern and the Treaty of Versailles,” Peace Palace Library, June 27, 2014,

3 “Rome Statute,” International Criminal Court, accessed August 20, 2019,

4 “Universal Declaration of Human Rights,” United Nations, accessed August 20, 2019,