III. Principle of Legality


Cassese, “The Principle of Legality” in International Criminal Law (3rd Ed., 2013) [draft version of chapter available for free online]

  • Cassese’s foundational text covers the main substantive and procedural aspects of international criminal law. The chapter on the “Principle of Legality” describes the principle and distinguishes varying articulations.

Gallant, The Principle of Legality in International and Comparative Criminal Law, Cambridge Studies in International and Comparative Law (2009) [available for free online]

  • Study of the status of legality in international law – in international criminal law, international human rights law, and international humanitarian law. Survey on legality/non-retroactivity in national constitutions and the principle of legality in various legal systems around the world.


Dana, Beyond Retroactivity to Realizing Justice: A Theory on the Principle of Legality in ICL Sentencing (2009) [available for free online]

  • This article seeks to develop the normative content of nulla poena sine lege (no punishment without law) under international law and critically evaluate the statutes of international criminal courts and their sentencing jurisprudence on genocide, crimes against humanity, and war crimes. The author argues for an understanding of nulla poena that it is not merely a protection against retroactive punishment, but is crucial to international criminal justice principles such as equality before the law, consistency in punishment, and legitimacy in international prosecutions.

Namwase, The Principle of Legality and the Prosecution of International Crimes in Domestic Courts (2011) [available for free online]

  • This study seeks to contextualise the discourse surrounding the principle of legality and the domestic prosecution of international crimes in Africa, focusing on the domestication of the Rome Statute in Uganda and the decision to prosecute domestically a former commander of the Lord’s Resistance Army. Ultimately, the paper finds that the principle of legality does not and should not bar prosecution of international crimes in Africa.

Van Schaack, Crimen Sine Lege: Judicial Lawmaking at the Intersection of Law and Morals, Georgetown Law Journal (2008) [available for free online]

  • This article notes that even where new standards have been applied to past conduct, these cases have not infringed on the principle of legality because today’s defendants were on sufficient notice of the foreseeability of ICL jurisprudential innovations in light of domestic penal law, universal moral values in international human rights law, developments in international humanitarian law, etc. The article argues that any lingering concerns about the rights of the defendants can and should be mitigated by sentencing practices that are closely tethered to extant domestic sentencing rules governing analogous domestic crimes.

Van Schaack, The Principle of Legality in International Criminal Law, ASIL Proceedings (2010) [available for free online]

  • In panel remarks, this professor discusses how ICL tribunals are applying new norms to past conduct and thus are engaged in a refashioning of ICL. However, this does not compromise the fundamental fairness of modern ICL proceedings because the jurisprudence is largely consistent with the international formulations of the principle of legality, authoritative interpretations emerging from institutions charged with enforcing human rights protections, and the purposes underlying the principles of nullum crimen sine lege.