This chapter analyses the Responsibility to Protect (R2P) in conjunction with the Protection of Civilians (POC) in peace operations. It examines where and how the two concepts have challenged, altered, led to reinterpretations and had feedback effects on each other. It does so through an examination of their: gradual institutionalization at the UN; deployment in the practices of the Security Council; and, influence over the actions of operations in the field. The analysis shows that the R2P has been in a co-evolution with POC and particularly the implementation of POC through UN peace operations. The chapter argues that the emergence of the R2P and the trends in POC in peace operations have cross-fertilized in discourse and practice at the UN regarding the prevention and response to egregious of human rights abuses. It argues that this has influenced the respective trajectories of the two concepts with ramifications for understanding the normative trajectory and status of the R2P as it enters its third decade in popular lexicon. In particular, it posits that the R2P’s normative status is more accurately depicted as a bundle of norms that intersect with, and sometimes rely on other norms, regimes and agendas.