International Criminal Law Overview

Principles

Definition

International criminal law is a distinct field of law and academic inquiry concerned with the definition, prosecution, and punishment of individuals for crimes that are considered to violate fundamental international norms and affect the international community as a whole. As a research concept, it investigates the normative framework governing grave offenses such as genocide, war crimes, crimes against humanity, and the crime of aggression, focusing on the principles of individual criminal responsibility, jurisdictional bases, and the procedural and institutional aspects of international and hybrid accountability mechanisms. Characterized by its evolving nature and the interplay between international and domestic legal systems, its significance lies in establishing accountability for perpetrators of mass atrocities, contributing to the prevention of such crimes, and upholding core values of international public order.

Ontological type

Core Crimes

Individual Responsibility

Jurisdiction and Admissibility

Key developments

Key Figures

Individual Accountability Consolidation era

During 1979-1994 international criminal law saw a consolidation of individual accountability as a central norm, linking personal liability for war crimes and crimes against humanity to both jus ad bellum and jus in bello. Antonio Cassese advanced the jurisprudential claim that individuals, not just states, can be prosecuted under international law and helped articulate the doctrinal bridge between armed conflict law and criminal responsibility. M. Cherif Bassiouni championed universal jurisdiction and codification, arguing for active enforcement mechanisms and procedural frameworks that made personal liability actionable across domestic and international venues. Ian Brownlie provided authoritativeness on how customary and treaty law converge to establish individual responsibility for core crimes, shaping penal theories and the normative grounds for later prosecutorial institutions.

Permanent Court Institutionalization era

Oona A. Hathaway [1] is a scholar affiliated with Harvard University [2] and the University of California, San Diego [3] in the Permanent Court Institutionalization era (1995-2008). Her key contributions in this era include analyzing how human rights commitments translate into durable judicial and enforcement mechanisms, as illustrated by Do Human Rights Treaties Make a Difference? [4], which emphasized that treaty design matters for the legitimacy and operability of a standing international court. Hathaway [1]'s work further argues that clear procedural frameworks and explicit jurisdiction are essential to enforceable accountability in the Permanent Court system during this era. By connecting institutional design to legitimacy, Hathaway's scholarship helped frame how permanent international criminal justice could be operationalized through cooperation and state compliance during 1995-2008, with Harvard University [2] and the University of California, San Diego [3] serving as intellectual anchors.

Multilevel Governance and Legitimacy era

Beth A. Simmons [1], affiliated with Harvard University [2] and the University of Pennsylvania [3], helped shape debates on international criminal law during the 2009-2023 era. Her key contribution in Can the International Criminal Court Deter Atrocity? [4] is the empirical claim that ICC deterrence is conditional on political support and credible procedures, illustrating how legitimacy and governance across levels determine deterrence outcomes. Through continued work at Harvard University [2] and the University of Pennsylvania [3], Simmons [1] emphasizes persuasion and coalition-building as mechanisms by which legitimacy is produced across domestic, regional, and international sites. Simmons' framework [1] clarifies how universal jurisdiction and transnational prosecutorial practices interact with governance legitimacy to shape enforcement and deterrence across levels in this era.