Soft war is ubiquitous today with the way the Islamic Republic of Iran characterizes its relationship with the West, and is a key concern of Iranian national security policy. Few, however, have seriously undertaken the task of defining what soft war is in concrete terms. This analysis proposes a definition of soft war grounded in Joseph Nye’s concept of ‘soft power’ and the history of Iran’s encounter with the West, particularly the United States. In this framework, soft war is the exercise of soft power by the United States on Iran, creating security challenges for the Islamic Republic and forcing the Republic to respond. This analysis not only explores the genealogy of this conflict and how it has unfolded under the Islamic Republic, but also attempts to assess the regime’s strategy in the soft war. This work can be an aid to policymakers, scholars, and others in better understanding soft war and its implications for Iran’s domestic politics and foreign affairs, in addition to U.S.-Iran relations.