The Project

International law is identified by observing what States say and do, and deriving rules from what States say and do. But what happens when States say or do nothing?

In 2018, the US, UK and France bombed Syria in response to the use of chemical weapons against civilians by the Assad regime. The UK declared that it lawfully used force because international law permits humanitarian intervention. Numerous other States remained silent. Does this mean that international law now permits humanitarian intervention? Further, in a number of disputes before the International Court of Justice, respondent States are not appearing; and since 2016, Russia and China have not appeared on five occasions before the International Tribunal on the Law of the Sea and arbitral tribunals.

State silence has the potential to erode fundamental rules, such as the prohibition of use of force, and to undermine international justice. But, it may also contribute to the dynamic evolution of international law. This project breaks new ground in international law by analysing if and under which conditions State silence has legal significance in international law, what is the reasoning behind the law for attributing (or not) any legal significance to State silence, and the reasons behind States being silent, including the reasons behind the silence of small or developing countries.

The project examines the practice of States across all geographic groups of the United Nations (UN), and the jurisprudence of at least 8 international courts and expert treaty bodies.