Can international community step up to defend civilians whose basic rights are been jeopardized? What is the limit of sovereignty in the face of a human rights crisis? Should international community been legitimated to take action in defense of helpless civilians? Who´s to determine when to act, if so? To address these and other question, this book will present you the concept of R2P – Responsibility to Protect. Throughout the work we will conduct you to analyze in which extent the responsibility to protect theory can influence the States behavior in intervention for human protection and discuss whether or not R2P has all the ingredients to be considered a customary international law. All of that will be done in the light of factual evidences conducting a comparative case study involving the interventions in Kosovo (late 1990's) and Libya (early 2010's). We will show and analyze changes in actions and procedures according to the new premises of R2P, addressing the legality of the intervention, the quickness of the response and the refrain in the use of veto power in the United Nations Security Council. If you are any interested in politics, international community and human rights, we invite you to travel together with us in this book for new concepts, reflections and a (potential) glimpse of the future.