This article situates the emergence of the Responsibility to Protect (R2P) concept, later accepted by many as a principle, in the wider flow of events following on the end of the Cold War. Among the hallmarks of change in the United Nations (UN) Security Council as of the early 1990s, in stark contrast to the Council’s preoccupations during its first four decades of activity, was its growing attention to humanitarian considerations relating to conflict, its new willingness to tackle conflicts (mainly internal ones) it might have avoided earlier, and its willingness to experiment with new approaches to resolving them. Just as worries over terrorism and the threat of weapons of mass destruction were to become dominant themes in its work, the humanitarian imperative also incrementally wove itself into the fabric of the Council’s decision-making. It is against this wider backdrop and that of several spectacular UN failures to prevent genocide and other mass humanitarian distress that UN Secretary-General (UNSG) Kofi Annan was impelled as of 1999 to look beyond existing international law and practice for a new normative framework, that while formally respecting the sovereignty of states nevertheless elevated humanitarian concerns and action to the level of an international responsibility to prevent the worst outcomes. Today R2P finds itself competing with other legal and diplomatic principles, but it remains a potent platform for advocacy and, at times, for action by the UN.