There is no greater foreign policy challenge facing the United States today than the one posed by the Islamic Republic of Iran. The Iranian regime’s persistent work on its nuclear program, and its intransigence in the face of international demands, has catalyzed a growing crisis that threatens international peace and security. So far, however, there has been little public discussion about the economic dimension of the current crisis, or of the financial levers available to the United States and its international partners to alter Iranian behavior.