Harmful Speech in International Law: Towards an Integrated Definition in International Criminal, Human Rights, and Humanitarian Law

Nowadays, instances of harmful speech, popularly known as hate speech, abound. Some of the most notorious are those uttered against the Rohingyas in Myanmar and the Palestinians in Gaza. The rise of harmful speech in society also leads, in part as a reaction to it, to a louder call to criminalise it, both at the national and international law level. This trend is evident in the law and practice of international criminal law, international human rights, and international humanitarian law (collectively, the ‘three regimes’). Yet, because there is no inherent hierarchy in international law, and given the three regimes’ different jurisdictions, the law on harmful speech has developed separately and somewhat haphazardly. In practice, this may mean that different international courts, such as the International Court of Justice and the International Criminal Court, both called to rule on the Myanmar and Gaza conflicts, might consider differently what harmful speech is and whether it constitutes a breach of international law. In turn, this may lead to legal uncertainty - for the speakers and the victims - and risks undermining the legitimacy of international law. This thesis thus attempts to formulate a common legal definition of harmful speech - including its more serious form, criminal harmful speech - across the three regimes.