The Rise and Fall of Proportionality: International Humanitarian Law and the American Way of War

In this talk,  Dr Boyd Van Dijk will trace the rise and fall of proportionality in U.S. government and military legal thinking. During the Vietnam War, U.S. officials initially resisted international restraints on air power, only to embrace proportionality later in the conflict as part of a “conservative revolution” in the laws of war.

This shift did not primarily aim to protect civilians but to preserve U.S. military effectiveness and legitimacy in the face of mounting global criticism. Proportionality subsequently emerged as the hegemonic principle for regulating civilian harm in targeting operations, reshaping international humanitarian law (IHL) for decades.

Today, however, this framework faces renewed contestation, not least under the Trump administration’s — and in particular the Secretary of Defense’s — direct attacks on IHL.

By emphasizing how remarkably recent proportionality’s emergence was, and how fragile it now appears, this lecture offers critical reflections on the uses, and limits, of law in constraining American war-making.

About the speaker

Dr Boyd van Dijk is a Senior Researcher at Sciences Po, Paris. He was a fellow at Nuffield College, Oxford and the Melbourne Law School, and taught previously at the London School of Economics, King's College London, Queen Mary, and the University of Amsterdam. His latest book, entitled 'Preparing for War,' came out in 2022 with Oxford University Press. It has received the 2023 Certificate of Merit in a Specialized Area of International Law from the American Society of International Law. He is now writing a new monograph on the practice of international law in armed conflict in the Global South after 1949 (under contract with OUP).
This event will be co-hosted by the Law School's Centre for International Law and Human Rights Implementation Centre.

Please register for the this event using the following link: https://www.eventbrite.co.uk/e/dr-boyd-van-dijk-tickets-1837532311609?utm-campaign=social&utm-content=attendeeshare&utm-medium=discovery&utm-term=listing&utm-source=cp&aff=ebdsshcopyurl

Contact information

For more information about this event, please contact law-exec@bristol.ac.uk