Some officials of Iran have recently renewed threats to close or exercise control over the Strait of Hormuz. Iran's threats appear to have been prompted by the likely imposition of new multilateral sanctions targeting Iran's economic lifeline - the export of oil and other energy products. In the past, Iranian leaders have made similar threats and comments when the country's oil exports have been threatened. However, as in the past, the prospect of a major disruption of maritime traffic in the Strait risks damaging Iranian interests. U.S. and allied military capabilities in the region remain formidable. This makes a prolonged outright closure of the Strait appear unlikely. Nevertheless, such threats can and do raise tensions in global energy markets and leave the United States and other global oil consumers to consider the risks of another potential conflict in the Middle East. This book examines the Iranian threats to the Strait of Hormuz and analyses the implications of some scenarios for potential U.S. or international conflict with Iran.