The Responsibility to Protect (R2P or RtoP) is a global political commitment which was endorsed by all member states of the United Nations at the 2005 World Summit in order to address its four key concerns to prevent genocide, war crimes, ethnic cleansing and crimes against humanity. The doctrine is regarded as a unanimous and well established international norm over the past two decades. The principle of the Responsibility to Protect is based upon the underlying premise that sovereignty entails a responsibility to protect all populations from mass atrocity crimes and human rights violations. The principle is based on a respect for the norms and principles of international law, especially the underlying principles of law relating to sovereignty, peace and security, human rights, and armed conflict. The R2P has three pillars: Pillar I: The protection responsibilities of the state – "Each individual state has the responsibility to protect its population from genocide, war crimes, ethnic cleansing, and crimes against humanity" Pillar II: International assistance and capacity-building – States pledge to assist each other in their protection responsibilities Pillar III: Timely and decisive collective response – If any state is "manifestly failing" in its protection responsibilities, then states should take collective action to protect the population. While there is agreement among states about the Responsibility to Protect, there is persistent contestation about the applicability of the third pillar in practice. The Responsibility to Protect provides a framework for employing measures that already exist (i.e., mediation, early warning mechanisms, economic sanctions, and chapter VII powers) to prevent atrocity crimes and to protect civilians from their occurrence. The authority to employ the use of force under the framework of the Responsibility to Protect rests solely with United Nations Security Council and is considered a measure of last resort.