This article examines the meaning and purpose of the Fundamental Principles of the Red Cross and Red Crescent Movement during and after decolonization. This was a period when the character of conflict experienced far-reaching changes, when the limitations of international humanitarian law were sharply exposed, and when humanitarian organizations of all kinds – the International Committee of the Red Cross included – redefined their missions and mandates. The Fundamental Principles were caught up in these processes; subject to a resurgent State sovereignty, they were both animated and constrained by the geopolitical forces of the era. The article pays particular attention to the politicization of the Principles in the contexts of colonial counter-insurgency, political detention and transfers of power.