Human rights law is often regarded as a discipline with aspirations of being an autonomous, self-contained regime within the general corpus of international law. Recent debates concerning reservations in the area of treaty law have reinforced views which claim the governing prinicples of human rights law depart – if not contradict – general rules of international law. By examining a landmark decision of the Inter-American Court of Human Rights which declared the recent purported Peruvian withdrawal from its compulsory jurisdiction invalid, against the background of general international law, the author aims to demonstrate that far from deviating from the general rules of the Vienna Convention of the Law of Treaties, this decision supports the view that human rights law is neither insulated from general international law nor divorced from the principle of sovereignty. For the principle of sovereignty has a twofold character: it is the fundament but also the limit of freedom of action by a state.