early developments

It was violations of the law of armed conflict that prompted discussion of the need for individual criminal prosecutions before international tribunals. Despite the proliferation of international rules governing armed conflict in the latter part of the nineteenth and early twentieth centuries, mechanisms for enforcing these rules were insufficient or absent entirely. ^{Footnote 13} The concept of international (or, at least, multinational) war crimes trials was not seriously discussed until the negotiations following the end of the First World War. ^{Footnote 14} However, the war crimes trials envisioned in the Treaty of Versailles never materialized. ^{Footnote 15} Germany convinced the Allies that it should conduct its own trials, which resulted, ultimately, in the domestic prosecution of only twelve military officers in Leipzig. ^{Footnote 16} Nonetheless, of note during this period was the 1919 report by the Allied Commission on the Responsibility of the Authors of the War and on Enforcement of Penalties, ^{Footnote 17} which is generally credited with originating the concept of crimes against humanity. ^{Footnote 18} However, this category of crimes was not included in the Treaty of Versailles.

During the inter-war period, there was academic debate and discussion at the Council of the League of Nations on the establishment of an international criminal court and an international penal code, but no real substantive advances were made. ^{Footnote 19} No state ratified the League of Nations’ Convention for the Creation of an International Criminal Court, and the enthusiasm for the establishment of an international criminal court and code subsided. ^{Footnote 20}

the influence of the second world war and its aftermath

The trials conducted after the Second World War were a turning point in international law in which it was made clear that individuals could be subject to legal obligations directly under international law and could be prosecuted for their violation. ^{Footnote 21} The Charter of the International Military Tribunal (Nuremburg Charter) granted the International Military Tribunal (IMT) jurisdiction over crimes against peace, war crimes, and crimes against humanity. ^{Footnote 22} Prosecutions for perpetrating a war of aggression, or crimes against peace, were in fact central to the trials in Nuremberg. ^{Footnote 23} Additionally, the long-recognized category of war crimes (violations of the laws or customs of war) was included in Article 6(b) of the Nuremberg Charter. More innovative was the inclusion, for the first time in a military tribunal’s jurisdiction, of crimes against humanity in Article 6(c). ^{Footnote 24} In light of the horrific acts perpetrated by the Nazi regime against German Jews and other German nationals, this category of crime was targeted at acts similar in nature to war crimes but committed against a state’s own nationals. ^{Footnote 25} The Nuremberg Charter also provided the blueprint for the proceedings against the Japanese leaders in Tokyo by the International Military Tribunal for the Far East, pursuant to the Charter of the International Military Tribunal for the Far East, and for the subsequent proceedings throughout Allied territory. ^{Footnote 26}

Also emerging from the horrific atrocities of the Second World War was the term genocide, which was coined by Raphael Lemkin in his 1944 book Axis Rule in Occupied Europe. ^{Footnote 27} The term was quickly adopted and used in the Nuremberg proceedings. Genocide was confirmed as a crime under international law soon after the end of the Second World War in a UN General Assembly resolution adopted unanimously at the end of 1946. ^{Footnote 28} The Convention on the Prevention and Punishment of the Crime of Genocide (Genocide Convention) was concluded soon thereafter, on 9 December 1948. ^{Footnote 29} The crime of genocide has repeatedly been recognized as a crime under customary international law, the prohibition of which is a peremptory norm of international law. ^{Footnote 30} The momentum displayed by states in adopting the Genocide Convention led to the separation of genocide from other international crimes. The development of those other crimes was delegated in 1947 to the ILC for further consideration. ^{Footnote 31}

Another important substantive development in the aftermath of the Second World War occurred in the field of international humanitarian law. In 1949, the four Geneva Conventions were adopted with a view to protecting victims of armed conflict. ^{Footnote 32} In an attempt to also advance the enforcement of the law of armed conflict, the Geneva Conventions included a grave breaches regime pursuant to which certain serious violations were subject not only to universal jurisdiction but also to mandatory prosecution or extradition by states parties. ^{Footnote 33} Despite these significant advancements in the wake of the Second World War, no international criminal trials occurred between the conclusion of the post-Second World War proceedings and the establishment of the ICTY almost fifty years later. ^{Footnote 34} The failure to establish a permanent international criminal court left the prosecution of international crimes to states. Occasions on which national courts exercised such jurisdiction were few and far between.

As mentioned earlier and further explored in the next section of this article, the UN General Assembly requested in 1947 that the ILC prepare a draft code of offences against the peace and security of mankind. Despite initial progress in the first half of the 1950s, there was a hiatus in the work of the ILC on the draft code after 1954 due to difficulties in defining the crime of aggression. Commentators have noted that the political implications of the Cold War prevented further development on an international criminal court. ^{Footnote 35} First, there was the unlikelihood of the major powers reaching an agreement on the definition of aggression. Second, establishing an international criminal court would involve the surrender of some degree of sovereignty, which the major powers were unwilling to do. ^{Footnote 36}

In the meantime, states focused on adopting international instruments dealing with specific crimes of international concern. ^{Footnote 37} These “suppression treaties” addressed the hijacking of aircraft, various defined acts of terrorism, drug crimes, crimes against internationally protected persons, and the recruitment of mercenaries, among others. ^{Footnote 38} These suppression treaties primarily operated by defining certain offences and obligating states parties to criminalize these offences under their own domestic laws (an “indirect enforcement system”). ^{Footnote 39} Additionally, they included obligations for inter-state cooperation. Thus, while the ILC returned to the task of drafting a code of crimes against the peace and security of mankind in the 1980s, states continued to regulate other specific crimes of international concern by treaty, such as corruption and transnational organized crime, including human trafficking, people smuggling, and firearms trafficking. ^{Footnote 40}

After an almost half-century hiatus in international criminal prosecutions, a renaissance in international criminal law occurred in the early 1990s. The UN Security Council revitalized the notion of prosecutions of international crimes before international tribunals with the establishment of the ICTY in 1993 and the ICTR the following year (ad hoc tribunals). Both of the ad hoc tribunals were established by the UN Security Council pursuant to its power under Chapter VII of the Charter of the United Nations (UN Charter) to act in situations of threats to the peace, breaches of the peace, or acts of aggression. ^{Footnote 41}

The ICTY was established in 1993 by the UN Security Council to hold accountable those who had committed serious violations of international humanitarian law during the conflicts attending the breakup of the former Socialist Federal Republic of Yugoslavia. ^{Footnote 42} It was given jurisdiction over crimes committed anywhere in the territory of the former Yugoslavia on or following 1 January 1991. In order to avoid violating the principle nullum crimen sine lege (which prohibits retroactive criminalization of conduct), the jurisdiction of the ICTY was limited to serious violations of international humanitarian law that were recognized as such and that entailed individual criminal responsibility, under customary international law at the time of their perpetration. ^{Footnote 43} This category of customary international humanitarian law was found to correspond in substance to “the Geneva Conventions of 12 August 1949 for the Protection of War Victims; the Hague Convention (IV) Respecting the Laws and Customs of War on Land and the Regulations annexed thereto of 18 October 1907; the Convention on the Prevention and Punishment of the Crime of Genocide of 9 December 1948; and the Charter of the International Military Tribunal of 8 August 1945.” ^{Footnote 44} Therefore, the subject matter jurisdiction of the ICTY was tied historically to the Nuremberg Charter and to those crimes that were defined shortly thereafter in the 1948 Genocide Convention and the 1949 Geneva Conventions.

The following year, in November 1994, the UN Security Council, again acting pursuant to Chapter VII of the UN Charter, established the ICTR to prosecute those responsible for the genocide and other serious violations of international humanitarian law perpetrated earlier that year in Rwanda. ^{Footnote 45} While the ICTR was unique for being the first international criminal tribunal to deal exclusively with a non-international armed conflict, the subject matter jurisdiction of the tribunal, for the most part, resembled that of the ICTY and included genocide, crimes against humanity, and war crimes. ^{Footnote 46}

The creation of these ad hoc international criminal tribunals was followed a few years later by the adoption of the Rome Statute, which created the first permanent International Criminal Court. During the process of negotiating the Rome Statute, delegates considered, but ultimately rejected, the inclusion of so-called “treaty crimes,” such as drug trafficking, within the jurisdiction of the court. ^{Footnote 47} Thus, the subject matter jurisdiction of the ICC is limited to four crimes as enumerated in Article 5 of the Rome Statute: genocide, crimes against humanity, war crimes, and aggression. The negotiation process on the subject matter jurisdiction of the ICC will be discussed later in this article in order to evaluate why other crimes were ultimately omitted from the Rome Statute. However, it is not hard to see that the Nuremberg Charter and a few other key developments in the wake of Second World War significantly shaped the jurisdiction of the ICC half a century later.

the ilc’s draft code of crimes

As noted earlier, in 1947, the ILC was given the task of developing a draft code of offences against the peace and security of mankind (draft Code) by the UN General Assembly. ^{Footnote 48} Almost fifty years later, in 1996, the final version of the ILC’s Draft Code of Crimes against the Peace and Security of Mankind (1996 Draft Code) included only five crimes: aggression, genocide, crimes against humanity, crimes against United Nations and associated personnel, and war crimes. ^{Footnote 49} By comparison, the 1991 version of the draft code (1991 Draft Code), provisionally adopted by the ILC on first reading, listed one dozen crimes, including international terrorism, illicit trafficking in narcotic drugs, and wilful and severe damage to the environment. ^{Footnote 50} These were all left out of the final version.

A still earlier version of the draft code had been completed by the ILC in 1951. It is important to remember that the ILC’s mandate was to create a draft code of offences against the peace and security of mankind and not a code of international crimes more generally. Therefore, as explained by one member of the ILC, “it would exclude all international crimes not directly aimed against the peace and security of mankind, such as the traffic in narcotic drugs, or the white slave traffic.” ^{Footnote 51} In addition to crimes derived from the Nuremberg Charter, ^{Footnote 52} the 1951 draft focused primarily on offences “which contain a political element and which endanger or disturb the maintenance of international peace and security.” ^{Footnote 53} This included acts constituting a threat or use of force by one state against another, organized terrorist activities, the fomenting of civil strife in another state by or with the acquiescence of state authorities, the violation of treaty obligations relating to international peace and security, genocide, inhuman acts against a civilian population, and war crimes. ^{Footnote 54} However, the notion of a “political element” was problematically vague and was criticized when the commission returned to its consideration of the topic in the 1980s. ^{Footnote 55}

A revised draft code, taking into account comments received from governments in response to the 1951 draft, was drafted in 1954 but contained only minimal changes to the 1951 list of crimes. ^{Footnote 56} Further progress then stalled for decades due to the inability of the international community to agree on a definition of aggression. ^{Footnote 57} The draft code was not discussed by the ILC for a twenty-seven-year period. In the meantime, as seen earlier, international efforts to address crimes of international concern resulted in a series of suppression treaties addressing crimes such as drug trafficking, specific acts of terrorism, and the employment of mercenaries. ^{Footnote 58} Consensus on a definition of aggression was finally achieved in 1974. ^{Footnote 59} However, it took another eight years before the draft code project reappeared on the ILC’s agenda in 1982. ^{Footnote 60}

The general sentiment among the members of the ILC at that time was that the scope of the draft code should be expanded beyond the 1954 version to take into account international instruments that had come into effect in the interim period. ^{Footnote 61} Moving away from a focus on the political motivation of crimes, the ILC now stated that the draft code should cover only “the most serious international crimes” and that “[t]his seriousness may be measured either by the extent of the calamity or by its horrific character, or by both at once.” ^{Footnote 62}

Proposed additions to the list of crimes included the use of nuclear weapons, colonialism, apartheid, serious damage to the environment, economic aggression, mercenarism, hostage taking and crimes against internationally protected persons, terrorism, drug trafficking, piracy, slavery and slave trading, and the hijacking of aircraft. ^{Footnote 63} However, the ILC itself tended not to favour such an expansive approach, emphasizing that “[t]he code ought to retain its particularly serious character as an instrument dealing solely with offences distinguished by their especially horrible, cruel, savage and barbarous nature.” ^{Footnote 64} Accordingly, ILC Special Rapporteur Doudou Thiam concluded that offences such as counterfeiting money, passport forgery, drug trafficking, and trafficking in obscene publications, among others, lay beyond the proper boundaries of offences against the peace and security of mankind. ^{Footnote 65}

By 1989, the ILC’s perspective on drug trafficking had shifted, and more members favoured, or at least accepted, its inclusion in the draft code. ^{Footnote 66} This shift came in the wake of the adoption in the previous year of the United Nations Convention against Illicit Traffic in Narcotic Drugs and Psychotropic Substances and coincided with a proposal by Trinidad and Tobago to revive the push for the establishment of a permanent international criminal court to deal, in particular, with the problem of drug trafficking. ^{Footnote 67} In addition to recognizing the severe health impacts of illicit narcotics, the ILC recognized that drug trafficking often goes hand in hand with acts of terrorism (“narco-terrorism”) and can have a destabilizing effect on some countries and could, therefore, even amount to a crime against peace. ^{Footnote 68} As one member of the ILC noted, even if drug trafficking was not being carried out by or on behalf of states, it was being perpetrated by “individuals or by multinational or transnational corporations which handled fabulous amounts of money and were a threat to Governments precisely because the resources they possessed were sometimes larger than the budget of the State in whose territory they operated.” ^{Footnote 69}

Illicit trafficking in narcotic drugs was therefore included in the ILC’s 1991 version of the draft code and maintained in a 1995 report in which the special rapporteur reduced the list of crimes to six offences “whose characterization as crimes against the peace and security of mankind was hard to challenge.” ^{Footnote 70} However, at this time, there was still “limited support” from states for the inclusion of illicit drug trafficking as a crime against the peace and security of mankind. ^{Footnote 71} Drug trafficking was ultimately left out of the final version, the following year, in an attempt to secure consensus among states on the text of the draft code.

While the crime of international terrorism was also included in the special rapporteur’s 1995 report, its inclusion in the draft code was questioned due to the absence of agreement on a sufficiently precise definition ^{Footnote 72} (a problem from which the crime of terrorism still suffers to date). ^{Footnote 73} It was similarly omitted from the final 1996 Draft Code. ^{Footnote 74}

As seen earlier, other crimes considered for inclusion by states when the ILC revisited the topic of the draft code in the 1980s included the crimes of colonialism and apartheid. ^{Footnote 75} In 1984, Special Rapporteur Doudou Thiam included these two crimes among those on which “there is wide international agreement ... should be placed at the head of the parade of the hideous monstrosities that constitute international crimes.” ^{Footnote 76} Doudou Thiam also included serious damage to the environment, taking of hostages, crimes against internationally protected persons, and mercenarism in the same category.

The crime of recruitment, use, financing, and training of mercenaries was also included in the 1991 Draft Code. However, when this version was circulated to states for comments, some states questioned whether it was sufficiently serious to warrant inclusion and whether it genuinely constituted a crime against the peace and security of mankind. The crime of intervention, which did not otherwise constitute the crime of aggression, attracted similar criticisms. These crimes, along with colonialism, apartheid, ^{Footnote 77} and the threat of aggression were omitted from the special rapporteur’s 1995 report in order to reflect the desire of the majority of states that had submitted comments. ^{Footnote 78}

While the scope of the draft code was thus significantly reduced at this time in order to reflect the positions of states, the special rapporteur and other members of the ILC expressed concern at the limited number of states that had submitted comments (only twenty-four). ^{Footnote 79} This was justifiably felt to be an insufficient response rate to be able to discern the general degree of support for the draft articles, and the draft code was criticized for reflecting the opinions of only a handful of states. ^{Footnote 80} Furthermore, the ILC noted, “third world countries had generally not expressed their views.” ^{Footnote 81} Despite this fact, a degree of political pragmatism was considered necessary in order to avoid “reducing the draft Code to a mere exercise in style, with no chance of becoming an applicable instrument.” ^{Footnote 82}

One crime that was considered for inclusion towards the end of the ILC’s work on the draft code was the crime of wilful and severe damage to the environment. ^{Footnote 83} In its final session on the draft code in 1996, a document prepared on this subject by ILC member Christian Tomuschat was presented to the ILC. ^{Footnote 84} The report concluded that the crime of attacks on the environment met the criteria of seriousness as well as the “required disruptive effect on the foundations of human society” and had the necessary political and moral support for its inclusion. ^{Footnote 85} Furthermore, it concluded that, in extreme circumstances, the ordinary rules of criminal law and inter-state cooperation would not be sufficient to deal with this type of crime. ^{Footnote 86} However, despite state support for inclusion of this crime, ^{Footnote 87} the ILC omitted it from the 1996 Draft Code. Instead, it included a more restrictive version of the crime under the category of war crimes. ^{Footnote 88} Of course, this version does not address attacks against the environment outside of armed conflict, which could be equally devastating. While time appeared to have run out for further discussion on the crime of attacks against the environment, the crime of attacking United Nations and associated personnel was included as a last minute addition. ^{Footnote 89}

Despite the fact that, at times, states as well as members of the ILC were willing to consider a rather expansive approach to the draft code, the final product was much more limited. Indeed, attacks against United Nations and associated personnel proved to be the only (and very late) addition to the list of crimes in the 1996 Draft Code, which went beyond those categories of crimes recognized in the immediate post-Second World War period. ^{Footnote 90} Although the ILC ultimately opted for a restrictive approach, it included the following caveat in its commentary on the first article of the 1996 Draft Code: “This provision is not intended to suggest that the Code covers exhaustively all crimes against the peace and security of mankind.” While much consideration was given to the potential inclusion of other crimes, recognizing, in particular, the severe effects of drug trafficking and attacks on the environment, these crimes were ultimately omitted in favour of an attempt to achieve consensus. ^{Footnote 91} Furthermore, certain crimes such as piracy and human trafficking were barely considered at all. As one commentator observed, “[i]nstead of the seriousness of the criminal conduct or of its effects, the Commission preferred tradition as the criterion of the definition of the crimes.” ^{Footnote 92}

drafting of the rome statute

In 1989, the push for the establishment of a permanent international criminal court was revived by Trinidad and Tobago, with the support of the member states of the Caribbean Community. ^{Footnote 93} These small countries were particularly concerned with criminal accountability for the crime of drug trafficking. ^{Footnote 94} Just under a decade later, the Rome Statute was adopted. ^{Footnote 95} However, the subject matter jurisdiction of the Rome Statute does not include illicit trafficking in narcotics or any other so-called “treaty-crimes.” As James Crawford has noted, “[i]t is a remarkable feature that the ICC’s subject-matter jurisdiction began as a longish list of crimes defined by existing treaties in force, and ended as a detailed specification of a few crimes under international criminal law, without explicit reference to any existing treaties.” ^{Footnote 96}

In response to the call for the establishment of an international criminal court by Trinidad and Tobago, the UN General Assembly instructed the ILC to consider this question within the context of its work on the draft code. ^{Footnote 97} The initial position of the ILC’s working group was that the jurisdiction of the proposed court should be derived from existing international treaties defining “crimes of an international character.” ^{Footnote 98} Accordingly, the working group’s preliminary consolidated draft text included a list of crimes defined by treaties in force, including genocide, war crimes (grave breaches of the Geneva Conventions and Additional Protocol I), ^{Footnote 99} hijacking of aircraft, apartheid, crimes against internationally protected persons, hostage taking, and unlawful acts against the safety of maritime navigation and fixed platforms on the continental shelf. ^{Footnote 100} The draft statute also contemplated that the court would have jurisdiction over crimes under “general international law,” as well as “exceptionally serious crimes” defined in national law pursuant to the suppression treaties (such as drug trafficking), with the explicit consent of the relevant states. ^{Footnote 101}

In 1994, the ILC adopted a draft statute for an international criminal court (ILC Draft Statute). ^{Footnote 102} This Draft Statute envisioned a court that would operate on the basis of state consent for all crimes other than genocide (for which the court would have inherent jurisdiction). ^{Footnote 103} The ILC noted that the ILC Draft Statute was “primarily an adjectival and procedural instrument” and that it was not its function to define new crimes or to codify crimes under general international law, thereby consciously electing not to use this opportunity to advance substantive international criminal law. ^{Footnote 104}

Article 20 of the ILC Draft Statute gave the court jurisdiction over the four main crimes under “general international law” — genocide, aggression, serious violations of the laws and customs applicable in armed conflict, and crimes against humanity. ^{Footnote 105} This article also refers to an annex that lists fourteen treaty crimes, including specific terrorist acts such as hostage taking and hijacking, grave breaches of the Geneva Conventions and Additional Protocol I, apartheid, torture, crimes against internationally protected persons, certain maritime crimes, and drug trafficking (subject to the jurisdictional requirement that they constitute “exceptionally serious crimes of international concern”). ^{Footnote 106}

Following the work of the ILC, the UN General Assembly first established an ad hoc committee to consider the ILC Draft Statute, which met in 1995, ^{Footnote 107} followed by a preparatory committee tasked with preparing “a widely acceptable consolidated text of a convention for an international criminal court.” ^{Footnote 108} The preparatory committee met over the course of 1996, 1997, and the early part of 1998. ^{Footnote 109} At the end of this period, it transmitted a draft statute for a diplomatic conference of plenipotentiaries to be held in Rome (Rome conference). This draft statute envisioned a court with inherent jurisdiction over genocide, aggression, war crimes, and crimes against humanity as well as the possibility of consent-based jurisdiction over other crimes such as terrorism, drug-trafficking, and crimes against UN and associated personnel. ^{Footnote 110}

Some states advocated for the inclusion of certain treaty crimes throughout the negotiations at the Rome conference, in part due to their seriousness, arguing that “the exclusion of these crimes from the Statute would constitute a serious lacuna in the jurisdiction of the Court.” ^{Footnote 111} However, many states favoured limiting the jurisdiction ratione materiae of the court to the three or four core crimes (war crimes, crimes against humanity, genocide, and, possibly, aggression). ^{Footnote 112} Reasons given for limiting the jurisdiction of the court included both normative and pragmatic arguments. For instance, some suggested that treaty crimes were inherently less grave than crimes under general international law. ^{Footnote 113} On the more pragmatic side, it was suggested that the jurisdiction of the court should be limited in order to ensure the broadest acceptance of the court by states, to limit the financial burden on the international community, to avoid the more complex jurisdictional rules that would be required by the inclusion of treaty crimes, and to avoid overloading the court. ^{Footnote 114} Ultimately, the pragmatic arguments promoting limited subject matter jurisdiction were persuasive to many states. As Neil Boister noted at the time, “it is argued that the ICC would be cheaper to start up and to run if it only had jurisdiction over core crimes, something which is almost certainly true. This is a stronger argument against inclusion of treaty crimes than most would concede.” ^{Footnote 115} Another consideration that favoured limited jurisdiction ratione materiae was the desire for automatic jurisdiction for the court (as opposed to a purely consent-based or opt-in system). ^{Footnote 116} This option was considered a necessary trade-off by many states. Finally, some commentators have suggested that powerful states also had political motivations for preferring restricted jurisdiction: they preferred existing arrangements for treaty crimes, and drug-trafficking and terrorism were considered “more likely to affect the direct political interests of Western states, and particularly the United States” than the core crimes. ^{Footnote 117}

At the end of the Rome conference, in addition to the Rome Statute, the participants adopted six resolutions. One of these resolutions recommended that, when a review conference of the Rome Statute was convened, it should revisit the possible inclusion of the crimes of terrorism and drug-trafficking. ^{Footnote 118} However, when the first Review Conference of the Rome Statute was convened in Kampala, Uganda, in June 2010 (Review Conference), the participants were primarily focused on reaching agreement on the definition of the crime of aggression. ^{Footnote 119} While other substantive proposals were made leading up to the Review Conference, a cautious approach was advocated, pursuant to which only those proposals that had general support would be put forward, “to avoid overburdening the Conference.” ^{Footnote 120} The view was expressed that the ICC was still in its early years and should focus on effectively fulfilling its existing mandate rather than an extended mandate at that time. ^{Footnote 121} Accordingly, discussion of the possible addition of the crimes of drug trafficking and terrorism was yet again deferred.

Following the Review Conference, a Working Group on Amendments began meeting to consider further substantive amendments to the Rome Statute. Proposed amendments included those on prohibited weapons submitted by Belgium, ^{Footnote 122} the use of nuclear weapons as proposed by Mexico, the crime of terrorism as proposed by the Netherlands, and drug trafficking as proposed by Trinidad and Tobago and Belize. ^{Footnote 123} However, the general sentiment remained that the ICC was already dealing with a number of challenges and was continuing to strive for universal support and, therefore, the time was still not ripe for expanding its subject matter jurisdiction. ^{Footnote 124} In 2013, the Netherlands withdrew its proposal to add terrorism to the subject matter jurisdiction of the court. ^{Footnote 125}

The establishment of a new permanent international criminal court was an opportunity for states to recognize other serious crimes of concern to the international community worthy of prosecution before this new court. Limiting the ICC’s jurisdiction to acts occurring prospectively meant that it would not be faced with the same nullum crimen sine lege concerns that limited the subject matter jurisdiction of the ad hoc tribunals. ^{Footnote 126} However, the drafters of the Rome Statute concluded that it was not meant to create and define new crimes beyond those that already existed in international law. ^{Footnote 127}

Undoubtedly, the adoption of a restrictive approach was significantly influenced by the political goal of trying to get as many states as possible to support the court and, ultimately, to ratify the Rome Statute. Furthermore, the brief time frames allocated to both the Rome Conference and the Review Conference prevented the inclusion of additional crimes. ^{Footnote 128} Finally, the ICC, since coming into operation, has continued to face practical and political challenges, leaving the soundness of expanding the ICC’s jurisdiction at this time in serious question. Ultimately, these factors combined to limit the ICC’s substantive jurisdiction to the core crimes.

threats to, or breaches of, international peace and security

The proliferation of international instruments regulating armed conflict in the latter half of the nineteenth and early twentieth centuries indicates that armed conflict was seen to be a situation of an exceptional nature deserving the attention of the international community as a whole. As Cassese explains in relation to war crimes, “[t]he exceptional character of war (a pathological occurrence in international dealings, leading to utterly inhuman behaviour) warranted this deviation from traditional law.” ^{Footnote 134} Since this body of law originated predominantly to govern international armed conflicts, these situations clearly involved breaches of international peace and security. They also represented situations of total breakdown of normal, functional inter-state relations.

It is beyond doubt that situations that threaten or breach international peace and security are of concern to the international community as a whole. This principle is embedded in the UN Charter and informs the primary purpose of the United Nations. ^{Footnote 135} The recent renaissance of international criminal law was triggered by the establishment of the ICTY and ICTR in the early 1990s by the UN Security Council, acting pursuant to its UN Charter Chapter VII authority to address “threats to the peace, breaches of the peace, and acts of aggression.” The history of the ILC’s attempts to create a draft code was also very much linked to peace and security considerations, as evidenced by the UN General Assembly’s mandate to establish “a draft code of offences against the peace and security of mankind.” ^{Footnote 136}

While situations of international armed conflict obviously fall into this category, situations of non-international armed conflict can also be found to constitute a threat to international peace and security. This can be seen in the UN Security Council’s establishment of the ICTR. ^{Footnote 137} Instability within one country can easily spill over and threaten neighbouring countries. With war crimes being the oldest of the currently recognized core crimes and with the continual attention paid by the international community to the crime of aggression, it is beyond doubt that a propensity to threaten or breach international peace and security constitutes one of the most significant doctrinal foundations for determining that a crime is one of “the most serious crimes of concern to the international community” that should be criminalized and prosecuted under international law.

state participation or systemic impunity

The constant rhetoric in international criminal legal circles concerning the need to end impunity for serious crimes indicates that there is a role for the international community in situations that may result in systemic impunity under national law. When individuals, for domestic systemic reasons, are unlikely to face prosecution in domestic courts for serious crimes, the argument is that an international system is needed to hold accountable those who would otherwise escape responsibility.

The involvement of state leaders in the perpetration of atrocities is often pointed to as a justification for international criminal law. ^{Footnote 138} The rationale for this argument is two-fold. First, state leaders control vast resources (financial, personnel, and military), which puts them in a position to perpetrate atrocities beyond the scale of any other potential perpetrator. ^{Footnote 139} State-led atrocity implies an inherent gravity as well as an abuse of a position of power. Second, it is unlikely that a government will hold trials of its own leaders. ^{Footnote 140} Therefore, unless there is a change of regime followed by domestic prosecution of past government leaders, state-led atrocities often result in systemic impunity for the perpetrators. ^{Footnote 141}

Consider the evolution of the definition of crimes against humanity. While a link to an international armed conflict was considered a necessary jurisdictional limitation on the IMT in prosecuting crimes against humanity, this link was dropped from the definition of crimes against humanity in the subsequent proceedings in Nuremberg pursuant to Control Council Law No. 10. ^{Footnote 142} Additionally, whereas a link to “other offences” was maintained in the ILC’s 1951 version of the draft code, this limitation was removed in its subsequent 1954 version. ^{Footnote 143} By removing the requirement of a connection to international armed conflict in the 1954 draft code, the ILC turned to another “internationalizing factor” for inhuman acts, namely that such acts were perpetrated “by the authorities of a State or by private individuals acting at the instigation or with the toleration of such authorities.” ^{Footnote 144}

Contemporary developments in international criminal law have moved away from this state-centric focus ^{Footnote 145} (with the exception of the crime of aggression, which is defined in the Rome Statute as the perpetration of an act of aggression “by a person in a position effectively to exercise control over or to direct the political or military action of a State”). ^{Footnote 146} Non-state actors have been prosecuted and convicted of international crimes at the contemporary international criminal courts and tribunals (including the ICC, ICTY, ICTR, and Special Court for Sierra Leone (SCSL)). This shift can also be seen in the ILC’s 1991 version of the draft code, which contained a provision on “systematic or mass violations of human rights.” This provision removed the requirement that the proscribed acts be perpetrated by or with the instigation or toleration of state authorities. Instead, it referred to the perpetration of specific violations of human rights “in a systematic manner or on a mass scale.” ^{Footnote 147} In its commentary, the ILC explained that “[i]t is important to point out that the draft article does not confine possible perpetrators of the crimes to public officials or representatives alone.” ^{Footnote 148} While recognizing the factual opportunities for state authorities to perpetrate mass atrocities, it noted that “the article does not rule out the possibility that private individuals with de facto power or organized in criminal gangs or groups might also commit the kind of systematic or mass violations of human rights covered by the article.” ^{Footnote 149}

Emphasis on the involvement of state actors in the perpetration of international crimes tends to presume that perpetration by non-state actors does not raise the same concerns of impunity because governments will be willing to prosecute the latter domestically. ^{Footnote 150} However, there are many reasons for which perpetration of certain acts by non-state actors might also raise concerns of impunity. ^{Footnote 151} These include the possibilities that governments may not control the entire territory of a state, that the devastating effects of armed conflict may have reduced the capacity of a state to conduct trials, ^{Footnote 152} or that domestic prosecutions of certain crimes may be undesirable. The latter factor may be particularly significant in circumstances of inter-ethnic violence, as prosecutions might raise questions about judicial impartiality or concerns about re-igniting tension or conflict. ^{Footnote 153} In short, the perpetration of international crimes by non-state actors may also give rise to situations of systemic impunity. Accordingly, there may be a role for the international community in ensuring that those who perpetrate serious crimes are held accountable, whether they are government actors or not.

crimes that “shock the conscience of humanity”

Discussions about the need to end impunity regardless of the status of the perpetrator tend to focus on the “extreme gravity of certain crimes” ^{Footnote 154} or the fact that the criminal conduct in question may “shock the conscience of humanity.” ^{Footnote 155} This shifts the focus from the status of the perpetrator to that of the norm violated. Focusing solely on the norm violated has been criticized as an insufficient criterion in and of itself because there are many crimes, such as murder, which are universally condemned but do not, as such, rise to the status of international crimes. ^{Footnote 156} Furthermore, as Robert Cryer rightly points out, “what is ‘shocking to the conscience of mankind’ is by no means a given.” ^{Footnote 157} Generally, it is the scale, gravity, and systematic perpetration of crimes, as well as those perpetrated with specific discriminatory intent, which have been found to “shock the conscience of humanity.” ^{Footnote 158} This can be seen in the contemporary definition of crimes against humanity and genocide. Crimes against humanity include certain proscribed acts when perpetrated “as part of a widespread or systematic attack directed against any civilian population,” and the definition of genocide focuses on the specific genocidal intent of the perpetrator in relation to a national, ethnical, racial, or religious group. ^{Footnote 159}

international or cross-border conduct

Another justification for the involvement of the international community in regulating and criminalizing certain conduct is the international or cross-border nature of the conduct. War crimes were recognized in international armed conflicts long before similar conduct was accepted as falling under the category of war crimes when committed in a non-international armed conflict. This reflects the traditional position that states were entitled “to deal with their own citizens more or less as they pleased.” ^{Footnote 160} This position began to shift with the prosecution of crimes against humanity at Nuremberg, the dawn of the international human rights era, and the extension of rules of international humanitarian law to non-international armed conflicts. ^{Footnote 161} However, it was not until 1995, with the ICTY’s first case, that it was confirmed that there was individual criminal responsibility under international law for war crimes committed in non-international armed conflicts. ^{Footnote 162} Despite these important advancements, states have traditionally been more willing to bring international or cross-border conduct under the purview of international regulation as opposed to conduct that occurs wholly within the territory of one state.

In addition to the sovereignty-based argument (that states should not interfere in the internal matters of other states), states may also consider international or cross-border conduct as more serious and more worthy of international attention due to the practical challenges faced by states attempting to prosecute such crimes domestically. ^{Footnote 163}

protected persons and vulnerable persons

It is also informative to look at the evolution of the treatment of core crimes by the contemporary international criminal tribunals and courts. The recognition of “new crimes” within the established categories of crimes against humanity and war crimes reveals some of the values and interests that the international community deems worthy of protection. For example, the crime of attacking peacekeepers was newly included as a war crime in the Rome Statute (whereas previously it had been criminalized through a suppression convention regime). ^{Footnote 164} It was subsequently included in the Statute of the Special Court for Sierra Leone, which entered the first convictions for this crime in 2009. ^{Footnote 165} The commentary to the Rome Statute observes that “delegations felt a need to explicitly condemn and criminalize attacks against humanitarian assistance and peacekeeping missions and thereby visibly signal the exceptional seriousness of such most serious crimes of international concern.” ^{Footnote 166} This crime recognizes that there are certain categories of persons who are worthy of special international protection based on the role they play in the international community.

Other examples of “new” crimes include the war crime of enlisting, conscripting, and using child soldiers ^{Footnote 167} and the expanded list of sexual violence crimes that can be found to constitute either war crimes or crimes against humanity. ^{Footnote 168} These crimes are based on the recognition that there are certain categories of vulnerable persons who have been deemed worthy of special protection by the international community, in particular women and children. ^{Footnote 169} For example, the preamble to the UN Declaration on the Rights of the Child recognizes that “the child, by reason of his physical and mental immaturity, needs special safeguards and care.” ^{Footnote 170} Similarly, the commentary to Article 4(3) of 1977 Additional Protocol II to the Geneva Conventions, which was the first international instrument to explicitly prohibit the recruitment of children into armed forces, observes that “[c]hildren are particularly vulnerable; they require privileged treatment in comparison with the rest of the civilian population.” ^{Footnote 171} In a similar vein, in the Report of the Secretary-General to the Security Council on the Protection of Civilians in Armed Conflict, the secretary-general noted that “[t]he breakdown of the social fabric and disintegration of families during times of armed conflict often leave women and girls especially vulnerable to gender-based violence and sexual exploitation, including rape and forced prostitution.” ^{Footnote 172}

balancing state sovereignty

Establishing a system of international criminal law based on the values and principles of the international community requires consideration not only of those principles that favour international criminalization but also those that may weigh against increasing the scope of international crimes. In particular, consideration must be given to the principle of sovereignty as entrenched in the UN Charter. ^{Footnote 173} A common criticism of the continued expansion of international crimes is the corresponding infringement on state sovereignty. ^{Footnote 174} The need to protect state sovereignty must be balanced with other factors that may be relied upon to justify the criminalization of certain conduct by the international community. However, the international criminal system has evolved with a view to safeguarding the sovereignty of states. For example, whereas the ICTY and ICTR were granted primacy in respect of domestic jurisdictions, ^{Footnote 175} the ICC operates on the principle of complementarity, whereby the primary obligation to prosecute lies with states. The ICC only has jurisdiction to prosecute in cases where states are unable or unwilling genuinely to prosecute perpetrators. ^{Footnote 176}

Furthermore, the discussion should not only focus on the doctrine of state sovereignty in the abstract. Consideration should also be given to its application in particular circumstances. For example, if countries suffering from certain types of criminality seek the international community’s help by, for example, including drug crimes within the Rome Statute’s subject matter jurisdiction, this should bear some weight in the debate on the approach to be taken. ^{Footnote 177}

a preliminary issue: understanding transnational crime in its broader context

While the core crimes focus on prohibited conduct in the broader context of widespread violence, the same approach is not taken with respect to transnational crimes in the suppression treaties. For example, it is not the crime of murder alone that qualifies as a core crime but, rather, murder committed in the context of a widespread or systematic attack against a civilian population (crime against humanity), ^{Footnote 178} unlawful killing perpetrated in the context of an armed conflict (war crime), ^{Footnote 179} or murder committed with the specific intent to destroy, in whole or in part, a protected group “in the context of a manifest pattern of similar conduct directed against that group or ... that could itself effect such destruction” (genocide). ^{Footnote 180} By contrast, the suppression treaties rely on domestic jurisdictions to criminalize conduct. Therefore, the offences proscribed in the latter more closely resemble other domestic crimes. For example, they include individual acts of unlawful possession, offering, sale, or transport of narcotic drugs. ^{Footnote 181} This different approach to criminalization may lead to comparisons between transnational crimes and core crimes that underestimate the aggregate harm caused by transnational crime. ^{Footnote 182}

Many of these transnational crimes are not perpetrated by individuals acting alone but, rather, in the context of large-scale, systemic criminality. ^{Footnote 183} Systemic and large-scale criminality can result in associated large-scale violence. Furthermore, the systemic and organized nature of certain types of criminality also suggests that the international community might best be served by pursuing the leaders and those at the top of criminal hierarchies (in the same way that the Office of the Prosecutor (OTP) of the ICC has stated that ICC prosecutions should focus on “those who bear the greatest responsibility” for the core crimes, such as leaders of government or of non-state armed groups). ^{Footnote 184} Large-scale systemic criminality associated with transnational organized crime can result in high levels of violence, corruption, and, ultimately, threats to the stability of states. In order to appreciate the impact of transnational crime, it cannot solely be viewed as individual conduct akin to ordinary domestic crime.

threats to, or breaches of, international peace and security

Transnational crime is not only committed for personal gain or other private purposes. Organized criminal activity such as drug trafficking can be used to fund insurgent groups and participants in armed conflict. ^{Footnote 185} As one UN document reveals, “Taliban insurgents earn at least US $125 million annually from the opium economy through taxation of cultivation, production and trafficking.” ^{Footnote 186} Similarly, the Autodefensas Unidad de Colombia (AUC), an umbrella organization of Colombian paramilitary groups, made an estimated 70 percent of its total income from the cocaine business in the late 1990s. ^{Footnote 187} Other examples include the Fuerzas Armadas Revolucionarias de Colombia (FARC) and the Ejército de Liberación Nacional (ELN) in Colombia and the Sendero Luminoso (Shining Path) in Peru. ^{Footnote 188} Recognition of this link between drug trafficking and illegal armed activity in both Peru (with respect to the Shining Path) and in Colombia (with respect to FARC) prompted the governments of those states to increase efforts to fight drug trafficking. ^{Footnote 189} As the World Drug Report 2012 states, “[e]fforts to reduce illicit drug production and trafficking helped to reduce the income of the illegal armed groups and thus their capacity to fight.” ^{Footnote 190}

Colombia has been the subject of preliminary investigation by the OTP of the ICC since 2004. The OTP has concluded that there is a reasonable basis to believe that crimes against humanity and war crimes have been perpetrated by both state and non-state actors, including the FARC, the ELN, and other paramilitary groups. ^{Footnote 191} Afghanistan has also been the subject of preliminary investigations by the OTP of the ICC. ^{Footnote 192} This demonstrates the often intertwined nature of transnational and core crimes.

Illicit trafficking in natural resources ^{Footnote 193} has also been a source of funding for armed groups, particularly in Africa, such as the diamond mines in Sierra Leone ^{Footnote 194} and the current illicit mineral smuggling in the Democratic Republic of the Congo (DRC). ^{Footnote 195} One group that has been cited as benefiting the most from illicit traffic in minerals in the DRC are the Forces Démocratiques de Libération du Rwanda (FDLR), ^{Footnote 196} a group whose top military commander stands charged with nine counts of war crimes in an outstanding arrest warrant issued by the ICC. ^{Footnote 197} The United Nations Office on Drugs and Crime (UNODC) has stated with respect to the DRC: “Until the mineral trafficking is addressed, the prospects for peace will be seriously undermined.” ^{Footnote 198}

Links between drug trafficking and organized crime as sources of funding for terrorist activities have also raised concern. ^{Footnote 199} It is not disputed that international terrorism constitutes a threat to international peace and security. The UN Security Council has affirmed this on multiple occasions. ^{Footnote 200} Other crimes of concern to the international community that are linked to terrorist organizations may similarly pose a threat to international peace and security. It has recently been reported that there are concerns about links between piracy in the Gulf of Guinea and funding of insurgent groups and terrorist organizations in the region. ^{Footnote 201} In the aftermath of 11 September 2001, the UN Security Council noted with concern “the close connection between international terrorism and transnational organized crime, illicit drugs, money-laundering, illegal arms-trafficking, and illegal movement of nuclear, chemical, biological and other potentially deadly materials.” ^{Footnote 202}

While international terrorism was not ultimately included in the Rome Statute’s subject matter jurisdiction, this was due primarily to difficulties in agreeing on a definition rather than to doubts as to the severity of the crime. Indeed, in the Final Act of the Rome Conference, the participants noted that terrorist acts “are serious crimes of concern to the international community.” ^{Footnote 203} Recently, the UN Security Council has reiterated its concern that “terrorists benefit from transnational organized crime in some regions, including from the trafficking of arms, persons, drugs, and artefacts and from the illicit trade in natural resources including gold and other precious metals and stones, minerals, wildlife, charcoal and oil, as well as from kidnapping for ransom and other crimes including extortion and bank robbery.” ^{Footnote 204}

The ability to profit from transnational organized crime is linked to the continuation of instability and insecurity. This can clearly be seen in the case of Afghanistan, which grows opium poppies used to produce 90 percent of the world’s heroin. ^{Footnote 205} As the UNODC explains, “[t]here is a symbiotic relationship between drug traffickers and the insurgency in Afghanistan, and both groups have an interest in prolonging the instability.” ^{Footnote 206} Furthermore, instability and insecurity often spills over to neighbouring countries.

Transnational crimes often have substantial destabilizing effects on countries and regions around the globe and can pose a threat to international peace and security. ^{Footnote 207} This has been recognized by the UN Security Council which “notes with concern the serious threats posed in some cases by drug trafficking and transnational organized crime to international security in different regions of the world.” ^{Footnote 208} In 2004, the High-Level Panel on Threats, Challenges and Change established by UN Secretary-General Kofi Annan concluded that transnational organized crime was one of the six major threats to international security with which the world is now faced. ^{Footnote 209} As the UNODC explains, “[c]ombating organized crime serves the double purpose of reducing this direct threat to State and human security, and also constitutes a necessary step in the effort to prevent and resolve internal conflicts, combat the spread of weapons and prevent terrorism.” ^{Footnote 210}

In West Africa, the trafficking of cocaine, among other forms of organized crime, has threatened stability in the region. ^{Footnote 211} This is not surprising when the value of a ton of cocaine in Europe exceeds the military budgets of some West African countries. ^{Footnote 212} The UNODC has observed that these illicit flows are not merely a consequence of weak governance in certain countries in the region but also a cause. ^{Footnote 213} It has also expressed concern that drug trafficking in the region could be used to fund non-state armed groups and terrorist organizations in the region such as Al Qaeda in the Islamic Maghreb (AQIM). ^{Footnote 214} Examples of situations in which drug trafficking has been linked to ongoing conflict include Afghanistan, Colombia, and Myanmar. ^{Footnote 215} The UN Security Council has also recognized on multiple occasions that the crimes of terrorism and piracy constitute threats to international peace and security. ^{Footnote 216} On this issue, the president of the UN Security Council has also expressed concern about other crimes including kidnapping, hostage taking, and cybercrime. ^{Footnote 217}

state participation and systemic impunity

Transnational crime is often characterized as being perpetrated by private actors without state involvement. ^{Footnote 218} An implication of this characterization is the suggestion that there is no need for prosecution of transnational crime at the international level because states will be willing and able to prosecute such crimes domestically. However, systemic impunity can arise in situations of large scale and systemic organized crime as a result of the power and influence of certain criminal groups, corruption, and violence. As Neil Boister recognizes, “[t]ransnational crime can in extreme cases undermine the internal sovereignty of states.” ^{Footnote 219}

In supporting the call of the Caribbean Community for the establishment of an international criminal court in 1989, the representative of Saint Lucia noted that “some domestic courts of middle-sized countries had been subjected to large-scale intimidation by powerful drug cartels.” ^{Footnote 220} Perhaps the most extreme example of this phenomenon is the so-called “narco-state.” ^{Footnote 221} The UNODC has noted that “[c]ocaine-related corruption has clearly undermined governance in places like Guinea-Bissau.” ^{Footnote 222} Allegations that drug-related corruption has permeated senior levels of the military and government are compounded by high levels of violence and intimidation. ^{Footnote 223} These factors, combined with an under-resourced police force and an absence of functioning prisons, demonstrate the inability of a country such as Guinea-Bissau to prosecute these crimes domestically. ^{Footnote 224} The UN Security Council has noted “the threats to national and subregional security and stability posed by the growth in illicit drug trafficking and organized crime in Guinea-Bissau.” ^{Footnote 225}

crimes that “shock the conscience of humanity” or impact vulnerable persons

Some transnational crimes, such as human trafficking, directly impact the same rights and values protected by core crimes. According to the UNODC, trafficking in persons is “a crime that is more accurately described as enslavement.” ^{Footnote 226} In fact, human trafficking is explicitly referred to in the definition of the crime against humanity of enslavement in the Rome Statute. ^{Footnote 227} However, the ICC can only exercise jurisdiction over human trafficking as enslavement when it fits under the chapeau requirements of crimes against humanity, namely when it is “committed as part of a widespread or systematic attack directed against any civilian population.” ^{Footnote 228} The question remains whether human trafficking deserves recognition as one of the “most serious crimes of concern to the international community” in its own right and not only when perpetrated in the context of crimes against humanity. ^{Footnote 229}

Not only does human trafficking violate the same norms that underlie crimes against humanity, it also impacts vulnerable groups in need of protection as identified by the international community. For example, an estimated 79 percent of victims of human trafficking are women and girls, and an estimated 22 percent are children (male or female). ^{Footnote 230} The gravity and scale of the crime is also substantial. The International Labour Organization estimates that 2.45 million people are in forced labour as a result of human trafficking. ^{Footnote 231}

Other transnational crimes that are superficially non-violent are often linked to high levels of violent crime when understood in the broader context of their systematic perpetration. The most obvious example of this is drug trafficking. ^{Footnote 232} For example, the increased violence related to the “drug war” in Mexico has resulted in an estimated 35,000 deaths in the period from 2006 to 2010. ^{Footnote 233} In comparison, the 2007–08 post-election violence in Kenya (which has given rise to a case of crimes against humanity currently before the ICC) resulted in an estimated 1,113–1,220 deaths. ^{Footnote 234} Thus, the impact of transnational crime, when considered in its broader context, may be found to “shock the conscience of humanity” due to its scale and severity.

international or cross-border conduct

The majority of non-core international or transnational crimes have either international or cross-border effects. This, of course, is inherent in the categorization of many of these crimes as international or transnational in the first place. In fact, some of the suppression treaties only apply to transnational or cross-border conducts. ^{Footnote 235} National responses are insufficient to tackle such crime. Successful prosecution in one country often results merely in the diversion of trafficking routes or displacement of the problem to another state. ^{Footnote 236} For example, at the same time that a successful campaign in Colombia reduced cocaine production in that country, manufacture of cocaine in Peru and Bolivia increased. ^{Footnote 237} Organized crime groups have proved sophisticated in their ability to adjust trafficking routes in order to prey on weaker states. This can be seen in the rapid expansion of cocaine trafficking throughout West Africa. ^{Footnote 238} As the UNODC has concluded, “[b]ecause [transnational organized crime] markets are global in scale, global strategies are required to address them, and anything else is likely to produce unwanted side effects, often in the most vulnerable countries.” ^{Footnote 239}