The Public Law(s) of Self-Defence

Event date
9 May 2024
Event time
12:45 - 14:00
Oxford week
TT 3
The Old Library - All Souls College and Online

Professor Russell Buchan, the University of Reading and Professor Patrick Capps, the University of Bristol

Notes & Changes

To join (whether in person or online), please complete the Registration Form above by 5:30pm on Wednesday 8 May 2024. The Zoom link will be sent after that time. Please note that if you register for online attendance after this time, a Zoom link may not be sent to you. If joining in person, registration is helpful but not essential.

The PIL Discussion Group's meetings are part of the programme of the British Branch of the International Law Association and are supported by the Law Faculty and Oxford University Press.


Grotius demonstrated that the right of self-defence is an uncontroversial and natural corollary of human nature that applies to all human interactions, including those involving states acting in international relations. We take this as a given and recognise that this right is established as a foundational and an inherent moral principle governing international life. This right is incorporated into international legal rules and principles found in custom, as well as in the international legal regimes governing collective security, state responsibility, and trade. There is, then, an established body of legal materials – such as Article 51 of the United Nations (UN) Charter (1945) and Article 21 of the Articles on State Responsibility (2001), alongside other treaties, state practice and international jurisprudence – which collectively form the content of the law of self-defence.

An account of the law of self-defence is implausible if it fails to take account of these materials. But it is incorrect to say that these materials stand up by themselves to determine the content of the law. Rather, an interpretative judgement of significance should be attributed to that material. Aspects of it come centre stage or take peripheral parts, or simply understood as simply mistaken. On occasion, even the Charter itself has been considered peripheral relative to evolving state practice. How is this judgement to be made? Our claim is that international lawyers invariably draw on one of three public law analogies – to an external state prerogative, an institutional enforcement power, or a justification – to answer this question.


Professor Russell Buchan

Russell Buchan is Professor of International Law at the University of Reading, UK. Russell has published widely in the field of public international law, including three monographs: International Law and the Construction of the Liberal Peace (Hart, 2013), Cyber Espionage and International Law (Hart, 2018), and (with Nicholas Tsagourias), Regulating the Use of Force in International Law: Stability and Change (Edward Elgar Publishing, 2021). He is also the co-editor of a number of edited collections and the co-editor in chief of the Journal of International Humanitarian Legal Studies.

Professor Patrick Capps

Patrick Capps is Professor of International Law at the University of Bristol, UK. Patrick's main area of research is the philosophy of international law. Patrick has published widely in this area including a monograph entitled Human Dignity as the Foundation of International Law (Hart, 2009) as well as mutliple articles and book chapters. His articles have appeared in leading journals including the Law Quarterely Review, Public Law, British Yearbook of International Law, Modern Law Review, European Journal of International Law, and Transnational Legal Theory.

Found within

Public International Law