What is the Responsibility to Protect (R2P) doctrine? Within the academic literature, we can see it labeled as falling under any number of theoretical constructs but most commonly as a norm or complex norm which is frequently viewed as being under challenged or best by contradictory forms of practice. In this chapter, I argue that we instead need to view the R2P doctrine as an international regime. This regime bundles together a number of previously existing legal and social norms. It also creates three new norms, reflecting the acceptances of responsibilities at the domestic and international levels and reflecting the primacy of the UN Security Council in addressing R2P issues. Such a perspective has significant benefits. It allows us to disentangle discrete elements of the R2P, and to identify that it is primarily Pillar Three of the doctrine which remains contested but also how the Security Council itself should respond to situations which fall within the scope of the doctrine. Focusing on the role of the Security Council itself, I argue, is therefore critical to understand wider concerns around the R2P. To do so, this chapter provides an overview of how this norm has evolved from the ICISS Report forward, how it remains contested, and how the Council has responded to potential violations of the R2P regime as its member states – particularly the US, UK and France – have engaged in repeated interventions to respond to the use of chemical weapons in Syria.