This chapter investigates the pattern by which the traditional State-centric approach to international law slowly but systematically yielded to emerging human rights norms in the post-Charter era which increasingly challenged the notion of State sovereignty and ultimately gave rise to the R2P doctrine. It first details some of the trends within the international legal system that facilitated R2P’s emergence, including the move from bilateralism to community interests as well as the push to impart obligations – rather than allowing discretion – upon third-party States to react to mass atrocity crimes. It then discusses R2P’s core tenets through the separate examination of the major documents that contributed to its formulation, including through an analysis of the legal value and levels of State support for each of these documents. The chapter ties these observations together to cast an overall picture of R2P as an emerging umbrella norm of various sub-norms which the doctrine seeks to pull together, repackage, and build upon.