Antonio Cassese, one of the most distinguished figures in international criminal justice, a respected scholar, judge and the first President of both the International Criminal Tribunal for the Former Yugoslavia (“ICTY”) and Special Tribunal for Lebanon (“STL”), died on 22 October 2011. His passing is a loss felt throughout the public international law community of which he was such a central figure.
Judge Cassese belonged to a class of progressive scholars whose vision and intellect aimed to change attitudes. He published extensively and taught international law to generations of students around the world. As a judge, he made a major contribution to fighting impunity and shaping the development of international criminal law. His driving force was to allow the “new” – post World War II – international law to do far more than simply “scratch the surface” of old, classic international law. He aimed to extend the legal framework of international armed conflict to non-international armed conflicts and he succeeded.
In both his academic and judicial work, Cassese adopted a broad approach to the applicability of customary rules to non-international conflicts early on in the 1970s. In 1975, prior to the adoption of Additional Protocol II to the Geneva Conventions, he published an article on the Spanish Civil War in an attempt to prove the existence of customary rules governing internal conflicts. Noting the paradox that allowed States to use weapons or methods of warfare forbidden in international conflicts on their own nationals in internal conflicts, he argued that a system of customary international law regulated all internal armed conflicts. It was, however, only in the 1990s that Cassese was granted the opportunity to re-shape international law in line with his strong convictions.
As presiding judge of the Appeals Chamber of the ICTY in the case of Prosecutor v. Duško Tadić (“Tadić”), Cassese drafted the 2 October 1995 Decision on the Defence Motion for Interlocutory Appeal on Jurisdiction answering the question whether the court had jurisdiction over crimes committed in non-international armed conflicts. The Appeals Chamber’s finding that customary international law recognised criminalisation of breaches of “laws or customs of war” in non-international conflicts was revolutionary. Up until that point, it had been held that Common Article 3 and Additional Protocol II to the Geneva Conventions did not provide a sufficient basis for individual criminal responsibility, unlike the “grave breaches” system established under the Geneva Conventions and Additional Protocol I. Only a year before that seminal decision of the Appeals Chamber in Tadić, the UN Commission of Experts on grave breaches in the territory of the former Yugoslavia formed under Security Council Resolution 780/1992 unanimously proclaimed that “there does not appear to be a customary international law applicable to internal armed conflicts which includes the concept of war crimes.”
The Appeals Chamber in Tadić based its contrary finding on a brief summary of State practice, beginning (unsurprisingly) with the Spanish Civil War but hardly reaching the “extensive and virtually uniform” threshold set by the International Court of Justice in the earlier North Sea Continental Shelf Cases. In a 2003 lecture at the New York University School of Law Cassese admitted setting up a team which took six months to go through State practice and come up with “a lot of evidence… well some evidence” which would “jettison this stupid distinction” that war crimes can only be committed in international conflicts. Cassese’s reverse methodology in establishing customary law created a tool of progressive development leading directly to the adoption of Article 8.2(d) of the Rome Statute of the International Criminal Court and Article 8.2(f), an almost verbatim reproduction of the Tadić definition of non-international armed conflict.
Today, the United Nations Security Council repeatedly calls for individual criminal responsibility for atrocities in civil conflicts; the Conventional Weapons Convention has been amended to include non-international conflicts; the UK Manual on the Law of Armed Conflicts accepts customary crimes in non-international conflicts and the International Committee of the Red Cross (“ICRC”) Study on Customary Law affirms individual criminal responsibility for war crimes in non-international armed conflicts. The Tadić decision had announced this development with great conviction back in 1995 by declaring “If international law… must gradually turn to the protection of human beings, it is only natural that the aforementioned dichotomy [between international and non-international conflicts] should gradually lose its weight”. Thanks to Antonio Cassese it did.
Naturally, Cassese’s complex and extensive legacy goes well beyond his contribution to the law applicable to non-international conflicts. His progressive signature is equally found, for example, on the first judgment confirming joint criminal enterprise as an established doctrine under customary international law which propelled this mode of liability into the most favoured prosecutorial tool of modern war crimes prosecutions. Such examples of his law-making drive demonstrate why Cassese was considered to be something of a maverick among traditionally discreet judges. He had little or no fear of challenging and changing basic precepts of international law and international criminal law. He was an outspoken visionary and, in the words of current President of the ICTY, Theodor Meron, “the architect of international criminal justice”. It is therefore no surprise that the Secretary General of the United Nations, Ban Ki-moon, described him as a “giant of international law” who “made a major contribution to fighting impunity and bringing about an age of accountability”.