The 2026 Antonio Cassese Prize for the best doctoral thesis in International Law has gone to Sebastian von Massow. He received the award, presented annually by the EUI Department of Law, at the EUI Conferring Ceremony on 19 June 2026.
Von Massow defended his thesis ‘Litigating colonial self-determination’ at the Department of Law in June 2025. It investigates how actors from Western Sahara and the Chagos Archipelago have turned to domestic, European, and international courts to pursue self-determination and to contest the legacies of colonial dispossession. Beyond charting litigation strategies, judicial reasoning, and outcomes, the thesis studies how Sahrawi and Chagossian communities themselves experience and remember that dispossession, drawing on socio-legal fieldwork, interviews, and close reading of court submissions to reflect on agency, resistance, and the limits of international law in struggles over decolonisation today.
Reflecting on the thesis, von Massow said: “I hope to take readers into the lived experience of what the denial of self-determination means today. Telling the story of the Western Sahara and Chagos litigations through the grievances of the people, the strategies of their lawyers, and the arguments they raised in courts around the world, I set out to refine our ideas about who does international law, where it gets done, and what it can achieve.”
In its motivation, the selection committee called the thesis beautifully written, logically structured, and subtly argued, and commended the original way it brings socio-legal research together with doctrinal analysis of international, regional, administrative, and colonial law.
The Antonio Cassese Prize is awarded annually by the EUI Department of Law for the best EUI doctoral thesis in International Law. It is named in honour of Antonio Cassese, one of the most distinguished figures in international law and international criminal justice.