Responsibility to Protect (R2P) aims to convert international conscience into timely and decisive collective action to rescue vulnerable communities. The choice is not whether international interventions will take place but where, when, how and under whose authority. Given the nature and victims of modern armed conflict, protection of civilians and populations at risk of mass atrocities is a core United Nations imperative. But while the UN has international authority, it lacks military power. Although its military might well have unmatched global reach, the United States acting unilaterally lacks international authority. This publication argues that progress towards good international society requires that force be harnessed to authority as the R2P moves from a universally validated principle to a routinely actionable norm.