In This Article Expand or collapse the "in this article" section War Crimes

  • Introduction
  • Primary Sources
  • Overviews of the Law of War Crimes

International Law War Crimes
Ioannis Kalpouzos
  • LAST MODIFIED: 15 January 2020
  • DOI: 10.1093/obo/9780199796953-0199


The law of war crimes consists of the criminalization of the violations of the law of armed conflict (LOAC), also known as international humanitarian law (IHL), leading to individual criminal liability. Accordingly, the understanding of the law requires a discussion of a) the underlying regime of the LOAC, its general principles, and their application in specific rules; b) the relation between LOAC/IHL and the international criminal law (ICL) of war crimes; and c) the process of criminalization and enforcement, often through judicial institutions. All three steps are necessary for a doctrinal as well as a critical historical understanding of the legal regime and an appreciation of the role that the concept of war crimes plays in the regulation of war. The literature is rich with references to these questions, and to the tensions inherent in the relations between legal regimes or the process of criminalization and enforcement. This is evident whether the sources address ICL as a whole, the relationship between ICL and IHL, the role of courts and tribunals, or specific (categories of) war crimes. An interpretation of the underlying principles of IHL, its relation to ICL, and the process of criminalization and enforcement will also determine the stance of an author when they intervene in the development of the law of war crimes, for example by commenting on recent jurisprudence. Over the 20th century, the literature has encompassed arguments for the expansion of applicable law as well as more skeptical or conservative interpretations. Alongside and through formalist doctrinal arguments, different positions in the literature are informed by different understandings of the proper balance in the regulation of war and in the development of international law.

Primary Sources

There has been a proliferation, and increasing sophistication, of online sources containing a wealth of primary material, partly in response to the (at least initially) limited functionality of court websites. ICC Legal Tools is an important project providing access to materials across international criminal law (ICL) and international humanitarian law (IHL). The latter is the focus of the seminal ICRC Customary IHL Database law study. Cryer 2019 is a very useful single-volume physical compilation.

  • Cryer, Robert. International Criminal Law Documents. Cambridge, UK: Cambridge University Press, 2019.

    Containing key and basic primary sources, including war crimes–related IHL treaty provisions, and the statutes of the major international criminal tribunals, this is a good starting point for the identification and study of the relevant treaty sources.

  • ICC Legal Tools.

    This database is limited to the International Criminal Court and contains a wealth of documents (statutes, judgments, preparatory works, etc.) related to a variety of ICL institutions, as well as other relevant institutional practice and scholarship.

  • ICRC Customary IHL Database.

    An important and continuously updated study, compiling relevant state practice structured over 161 rules of IHL. Some of these refer explicitly to war crimes, while the material provided for the support of IHL rules also often includes ICL material. While it is important not to treat the study itself as a primary source, it is both extremely useful and considered authoritative by many, if not all, commentators.

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