Sometimes, in the context of prosecuting international crimes, the term “international criminal justice” is used. In terms of what this concept means, as the late Antonio Cassese observed: The term international criminal justice is considered to be a vague concept. What is often meant by it is the application of the principle of accountability for some international crimes, before a national or an international judicial body. Such a body must, however, be duly constituted and impartial, and its legal processes must be fair and it must be in accordance with the international standards.
For the current purposes, the term is used to refer to international crimes that terrorists may be prosecuted for, whether they are treaty-based crimes of terrorism – i.e. their legal source is an international treaty such as one of the universal conventions against terrorism or one of the core customary international crimes e.g. crimes against humanity. Although the latter do not expressly deal with terrorism related crimes, as will be explained below, in certain circumstances they can extend to terrorism-related crimes. Both of these international crimes form the basis of international criminal law, which is a body of public international law. Notably, in contrast to the other international legal regimes underpinning the United Nations CT Strategy, a fully coherent international criminal law regime, with accompanying mechanisms, governing terrorism and counter-terrorism does not yet exist.
In terms of its sources, whilst international criminal law is founded on article 38(1) of the Statute of the International Court of Justice, the exact legal source, scope and parameters of any international crime will often be determined by the legal instrument of the statute of the organ in which the crime is prosecuted. This can lead to some divergences in approach, including if and how terrorism-related crimes may be directly or indirectly prosecuted as international crimes. In turn, generally, an international crime attacks the fundamental values of the international community, such as peace and security, including due to the systematic or large-scale violence involved.
In terms of where these international crimes are prosecuted, with the exception of the Special Tribunal for Lebanon, there are no international criminal courts or tribunals with dedicated jurisdiction over terrorist crimes. Some of the most heinous and high-profile cases may be heard by an international criminal court or tribunal, such as the International Criminal Court, the jurisdiction of which is sourced in the Rome Statute of the International Criminal Court 1998 (Rome Statute). Alternatively, an ad hoc criminal tribunal may be created, such as those for former Yugoslavia and Rwanda, which are sourced in special Statutes provided by Chapter VII Security Council resolutions. On occasion, a hybrid court may be created, such as the Special Court for Sierra Leone or the Extraordinary Chambers in the Courts of Cambodia, which are sourced in both international and domestic law.
Usually, however, terrorist crimes fall into the category of national criminal law of international concern. As such, they will be prosecuted by a national court where these crimes have been incorporated into national law, whether under a monist or dualist system. For example, domestic legislation criminalizing genocide, war crimes and torture is often enacted to implement a State’s obligations under the Genocide Act 1948, the Geneva Conventions 1949 or the Convention against Torture 1984. In addition, their respectively articulated crimes can exist under customary international law on which some national courts will rely directly without the need for further legislation.
As such, the criminal justice response to terrorism is therefore essentially framed by national law, which itself must comply with various aspects of international law. There are thus several components of international law that are directly relevant to the national criminal justice response to terrorism. In addition to treaty-based obligations stemming from their ratification of the universal legal instruments against terrorism and several legally binding obligations imposed through the relevant Security Council resolutions on counter-terrorism, States also have a number of legal obligations under other branches of international law, including international human rights, humanitarian, refugee and customary international law.
Security Council resolution 1373 (2001) requires States to refrain from providing any form of support to entities or persons involved in terrorist acts, including by eliminating the supply of weapons to terrorists. In its resolution 2370 (2017), the Council urges States to act cooperatively to prevent terrorists from acquiring weapons and calls upon them to counter threats posed by Improvised Explosive Devices (IEDs) and to become parties to related international and regional instruments. Because of the constantly evolving nature of the operational terrorist environment, denying terrorists access to weapons is a complex and multifaceted challenge. Illicit trafficking in weapons is often associated with, and facilitated by, other forms of organized crime, including terrorism. Weapons may fall into the hands of terrorists because of poorly secured stockpiles and weak border controls. The activities of FTFs further increase the probability that weapons and ammunition will cross borders.
Coordinated and comprehensive Border Management (CBM) strategies, which require close coordination among the competent authorities, have proven to be a highly effective tool for efficiently and effectively managing national borders. CBM strategies provide for coordination of policies, programmes, and delivery among cross-border regulatory agencies with the aim of strengthening the management of trade and travel flows, while also addressing security concerns. The Security Council’s 2015 Madrid Guiding Principles (S/2015/939) call on States to consider incorporating CBM principles in order to enhance the effectiveness of border security aimed at stemming the flow of FTFs.
Ensuring effective border security is an integral part of any comprehensive and integrated national counter-terrorism strategy and requires collective action by States and relevant international and regional organizations. The Committee and CTED can assist States to identify gaps, needs and challenges, as well as to facilitate the sharing of good practices in this area and facilitate the delivery of technical assistance to ensure implementation of the relevant Council resolutions and the Committee’s related recommendations.
 (Adapted from UNODC 2018. Module 4)