This paper informs the US policy response to a nuclear-armed Iran. Specifically, it addresses whether or not the United States should provide security guarantees for its allies in the Middle East. The Introduction sets the stage by describing the current trajectory of the Iranian nuclear weapons program and the likely ramifications of Iranian acquisition. It provides the analytical framework for the case studies that follow. Chapter 1 is a case study of France and its decision to develop a national nuclear weapons capability despite the US security guarantee. This chapter reveals that security considerations are but one of many factors that may contribute to a country initiating a nuclear weapons program. It also displays the fragility of US credibility. Chapter 2 is a case study of Taiwan. It demonstrates the power of a junior ally in driving the security relationship and provides a caution against entangling alliances. It also highlights the importance of economic aid and military sales as critical enablers of any security guarantee. Chapter 3 studies the case of South Korea. This chapter examines the implications of forward deployed troops and underscores the difficulty in forming multilateral security regimes. Chapter 4 applies the lessons learned from the three case studies to the current situation in the Middle East. In total, these cases offer a sharp warning to the United States as it considers extending formal security guarantees to its Middle East allies. This paper offers the broad contours of a new Middle East security framework and recommends that the United States avoid adopting new formal security relationships. Rather the United States should update the Carter Doctrine, work to rebuild its bilateral relationships in the region, and continue to provide the requisite assistance and presence to deter Iranian aggression and forestall the further spread of nuclear weapons.
