The Role of the International Criminal Tribunal for the Former Yugoslavia in the Institutionalization of International Criminal Justice
The International Criminal Tribunal for the former Yugoslavia (ICTY) emerged from an urgent demand for criminal accountability in the wake of mass atrocities and marked a decisive turning point in the evolution of international criminal justice. Established in 1993 by the United Nations Security Council under Chapter VII of the UN Charter, the Tribunal represented an unprecedented legal response to serious violations of international humanitarian law committed on the territory of the former Yugoslavia. This article examines the research question of how the ICTY’s denial of immunity for state officials and prosecution of high-ranking officials redefined individual criminal responsibility, and what this means for contemporary international justice efforts.
Immunity of State Officials in International Law: Between Sovereignty and Accountability
Immunity of state officials, under international law, refers to the legal protection that prevents national courts of one state from exercising criminal jurisdiction over foreign officials for acts connected to their official functions or status. The doctrine of immunity of state officials was largely consolidated in the period following the establishment of the United Nations, within the broader process of codification of international law and the strengthening of the international legal order. Historically, the concept of immunity in its contemporary form was not recognized, given the functioning of international systems in different historical periods and the fact that states were not structured around the modern concept of statehood and sovereignty. As a result, the protection of state officials was often ensured through non-peaceful means, including political pressure or the use of force, rather than through institutionalized legal mechanisms.
In its narrow legal sense, immunity does not constitute a mechanism that renders state officials untouchable or grants them unlimited power. Rather, it represents a functional form of protection against the exercise of external criminal jurisdiction, particularly in cases involving politically motivated or selective prosecutions. Accordingly, the primary purpose of immunity is not to privilege the individual exercising an official function, but to preserve the sovereign equality of states and to uphold the principle of non-intervention in the internal affairs of other states, which remains a cornerstone of the international legal order.
International law recognizes two principal forms of immunity: personal immunity (ratione personae) and functional immunity (ratione materiae). Personal immunity applies to a limited category of high-ranking state officials, namely Heads of State, Heads of Government, and Ministers for Foreign Affairs. It is absolute in nature during the period in which the official holds office and covers both official and private acts. Functional immunity, by contrast, applies to all state officials with respect to acts performed in an official capacity and continues to produce legal effects even after the termination of the official’s mandate, insofar as the acts in question qualify as acts of the state.
Developments in international criminal justice, however, have significantly challenged the traditionally absolute character of the immunity of state officials. The establishment of the International Criminal Tribunal for the former Yugoslavia (ICTY) marked a turning point in the history of international criminal law. Its Statute opened a new chapter by affirming the principle of individual criminal responsibility for serious international crimes, irrespective of official status. During its mandate, senior political and military officials from the former Yugoslavia were prosecuted and tried for international crimes, notwithstanding their official positions, thereby directly challenging the traditional concept of immunity of state officials and reinforcing the principle that the most serious international crimes cannot be shielded by official capacity.
In this context, the immunity of state officials can no longer be regarded as unlimited, as clear and increasingly consolidated exceptions have emerged under international law. While state officials generally enjoy immunity before the national courts of their own state and, in certain circumstances, before the courts of other states, such immunity does not apply before international criminal tribunals. This is particularly evident in cases involving international crimes such as genocide, crimes against humanity, and war crimes, as explicitly provided for in the statute of the ICTY. Similarly, the Rome Statute of the International Criminal Court, as a normative continuation of the practice established by the ICTY, enshrines in Article 27 the principle of the irrelevance of official capacity, emphasizing that immunities or special procedural rules attached to official status shall not bar the court from exercising its jurisdiction. One of the most authoritative efforts to codify this area of law is reflected in the work of the International Law Commission of the United Nations, which between 2017 and 2022 prepared the Draft Articles on the immunity of state officials from foreign criminal jurisdiction. These Draft Articles seek to establish explicitly that functional immunity (ratione materiae) does not apply in respect of the most serious international crimes, including genocide, crimes against humanity, war crimes, the crime of apartheid, torture, and enforced disappearance, thereby reflecting the progressive development of customary international law. Within this normative framework, the Vienna Convention on Diplomatic Relations and the Vienna Convention on Consular Relations also occupy a significant place. These instruments regulate the immunities and privileges of diplomats and consular officials in the receiving state and provide, inter alia, immunity from the criminal jurisdiction of the receiving state for acts performed in the exercise of official functions. This includes protection against criminal prosecution by the authorities of the receiving state and reflects the necessity of ensuring the independent and effective performance of diplomatic and consular missions in international relations.
The Development of the Doctrine of Individual Criminal Responsibility: Redefining Accountability through the ICTY’s Denial of the Immunity of State Officials
The doctrine of individual criminal responsibility in international criminal law finds its origins in the Nuremberg and Tokyo Tribunals. However, despite the historical importance of these tribunals, individual criminal responsibility had not yet been consolidated as a stable and universal norm of international law. A qualitative and normative development of this doctrine occurred with the establishment of the International Criminal Tribunal for the former Yugoslavia (ICTY), where this principle was institutionalized and explicitly integrated into the international legal framework. Article 7 of the ICTY Statute expressly provides that any person who planned, instigated, ordered, committed, or otherwise aided and abetted in the planning, preparation, or execution of crimes falling within the Tribunal’s jurisdiction bears individual criminal responsibility. In this way, the ICTY marked a significant historical turning point by establishing individual criminal responsibility as an integral norm of international criminal law.
The importance of this development is further reinforced by the fact that the Tribunal was established by the United Nations Security Council, rather than by the victorious powers of a conflict, as had been the case with earlier tribunals. This conferred far broader international legitimacy on the principle and distanced it from perceptions of selective or victor’s justice. A particularly significant element of the ICTY Statute is the explicit exclusion of the immunity of state officials. Article 7(2) stipulates that the official position of an individual, whether as Head of State or a senior government official, does not exempt that person from criminal responsibility, nor does it constitute grounds for mitigation of punishment. This provision represents one of the most important moments in the history of international criminal law, as it marks the erosion of the traditional principle of absolute immunity of state officials before international criminal justice.
A particularly distinctive feature of the ICTY is that it was established in the middle of an ongoing conflict in the former Yugoslavia in 1993, unlike previous post–World War II tribunals, which prosecuted officials only after hostilities had ceased and political regimes had fallen. The ICTY arrested and prosecuted state officials while they were still holding office and exercising their official functions. This represented a major break from the traditional idea that state officials were inviolable during their tenure. Accordingly, on 24 May 1999, Slobodan Milošević became the first sitting head of state to be indicted for war crimes by an international tribunal. As the Prosecutor, Carla Del Ponte, stated in her opening remarks at the trial of Slobodan Milošević, “This Tribunal, and this trial in particular, give the most powerful demonstration that no one is above the law or beyond the reach of international justice.”
During proceedings before the ICTY, attempts were made in certain cases to invoke state immunity as a legal barrier to the prosecution of senior officials. A particularly illustrative example is the Slobodan Milošević case, where, in decisions on preliminary motions, the Trial Chamber was confronted with arguments challenging the Tribunal’s jurisdiction on the basis of Milošević’s status as former President of the Federal Republic of Yugoslavia. These arguments were not raised directly by the accused but were submitted by amici curiae (friends of the court). Nevertheless, the Trial Chamber held that there was no legal basis to contest the validity of Article 7(2) of the Statute, emphasizing that this provision reflects a rule of customary international law.
The ICTY’s handling of state officials established a clear precedent that neither political status nor official status shields individuals from accountability for serious international crimes. By firmly rejecting claims of immunity, the Tribunal reinforced the principle that international criminal law applies equally to all, strengthening the authority and legitimacy of international justice.
Gaza and International Criminal Justice Today: What ICTY Teaches Us (and What Was Not Learned)
Although the ICTY is often criticized for its limited impact on reconciliation and peace, as well as for the incomplete justice it provided to victims, such criticism raises a broader and more fundamental question for international criminal law: what happens in situations where no real accountability mechanism exists? Despite persistent skepticism, the ICTY represents a successful institutional structure in terms of establishing individual criminal responsibility for crimes committed in the former Yugoslavia. Its historical and legal contribution is indisputable, particularly in its prosecution of high-ranking state, political, and military officials, thereby definitively dismantling the myth of the untouchability of power in the face of international justice. The ICTY demonstrated that even in the context of armed conflict, criminal prosecution of individuals responsible for international crimes is not only possible but necessary.
Since the conclusion of the ICTY’s mandate, however, the world has faced new conflicts characterized by mass violence against civilians. This raises the question of whether the ICTY succeeded in creating a sustainable precedent and whether the international community truly learned from its experiences and limitations. While this question may appear rhetorical, reality suggests that the world, and particularly the United Nations, has failed to adequately internalize both the so-called “mistakes” and the normative achievements of the ICTY. This failure is especially evident in the context of the current situation in Gaza. Since the escalation of violence in October 2023, international humanitarian law and international criminal law have faced a genuine existential challenge. Crimes are widely reported, victims are visible, and violations are continuously documented, yet a serious and functional initiative for investigating and prosecuting international crimes remains absent.
The genocide in Gaza highlights the direct consequences of the lack of an effective accountability mechanism. Rather than preventing crimes, the absence of justice appears to create an environment that facilitates and normalizes them. Gaza today represents a context in which individual criminal responsibility remains abstract: crimes occur in real time, while justice is equally absent in real time. In stark contrast, the ICTY was established precisely at a moment when crimes in the Balkans were still being committed. Despite its limitations and the skepticism surrounding it, the Tribunal conveyed a fundamental message: individual criminal responsibility is not a post-conflict luxury nor a process to be deferred until peace is achieved. Instead, the ICTY demonstrated that justice can and should function in parallel with conflict, as an integral component of international order and accountability.
Impunity and inaction in holding perpetrators of international crimes accountable not only undermine the credibility of the international justice system, but also jeopardize the effectiveness and legitimacy of international law as a whole.
