'The themes of prophets and prophecy have been too long ignored by political theorists. In this brilliant new study, James Murphy makes the case for the prophetic voice as the 'third sword' in politics. Surveying cases from Nathan, Socrates, and Jesus to Joan of Arc, Thomas More, and Martin Luther King, Murphy defines the prophet by the capacity to say 'No.' It is this willingness to heed the voice of conscience and resist the allure of power that makes the prophet such an enduring and often maddening archetype. This book is a must read for every serious political theorist.' Steven B. Smith, Yale University