This article focuses on the analysis by the International Court of Justice of the principle of non-intervention in domestic affairs in its judgment of 27 June 1986 in the case concerning Military and Paramilitary Activities in and against Nicaragua and contrasts it with the evolution of international law and practice in this field. It is proposed that the Court's 1986 analysis not only remains of actuality today, but also constitutes a precursor to legal developments that have since taken place. This is particularly the case with regard to the relationship between the protection of human rights on the one hand and the safeguard of state sovereignty and the collective security regime on the other. The 1986 judgment helped to clarify the content of humanitarian assistance. It constituted the starting point for the development of this concept in a series of GA resolutions that were subsequently adopted. The controversial doctrine of ‘humanitarian intervention’, as well as state practice in violation of this principle, in no way led to modifying existing international law. Similarly, the new concept of ‘responsibility to protect’, which places emphasis on collective security and discounts unilateral action, has not led to the disappearance of the principle of non-intervention either.