This chapter argues that one of the main ways of understanding the societization of diplomacy—the theory and practice of Soft Power—is now so diminished as to constitute the end of an era. It posits the idea of Reputational Security as a substitute. The chapter explains core elements of Reputational Security, including its openness to collective work, its connection to the core business of the state, and its linkage to reform. It considers future development of the approach using the well-known five-element model of public diplomacy: listening, advocacy, cultural diplomacy, exchange diplomacy, and international broadcasting. It concludes that the reputations of western countries and especially the United States are fragile, and countries that fail to work together to address the shared challenges of our era will be judged critically, eroding both reputation and—by implication—security.