Since the Islamic Revolution in Iran in 1979, a priority of U.S. policy has been to reduce the perceived threat posed by Iran to a broad range of U.S. interests. However, a common enemy has emerged in the form of the Islamic State organization, reducing gaps in U.S. and Iranian interests. During the 1980s and 1990s, U.S. officials identified Iran's support for militant Middle East groups as a significant threat to U.S. interests and allies. A perceived potential threat from Iran's nuclear program emerged in 2002, and the United States has orchestrated broad international economic pressure on Iran to try to compel it to verifiably confine that program to purely peaceful purposes. The pressure has harmed Iran's economy and might have contributed to the June 2013 election as president of Iran of the relatively moderate Hassan Rouhani, who campaigned as an advocate of ending Iran's international isolation. Subsequent multilateral talks with Iran produced an interim agreement ("Joint Plan of Action," JPA) that halted the expansion of Iran's nuclear program in exchange for modest sanctions relief. As the November 24, 2014 deadline for the JPA expiration approaches, the United States and its partners are negotiating intensively to reach a comprehensive agreement on the nuclear issue, but significant differences reportedly remain. A final nuclear agreement would further improve U.S.-Iran relations. Senior level U.S.-Iran talks are held regularly, primarily on the nuclear issue but also including regional issues such as how to defeat the Islamic State organization. U.S. officials have raised with their Iranian counterparts the issue of American citizens detained in Iran. The nuclear negotiations also have eased tensions between Iran and its neighbors in the Persian Gulf region-all allies of the United States. However, the Gulf states, Israel, and other regional states express concern that an Iran that is reintegrated into the region and the international community would give Iran additional resources to support movements and regimes that oppose U.S. and U.S.-allied interests. State Department reports on international terrorism assert that Iran continues to provide funds and arms to a wide range of movements, including Lebanese Hezbollah, Hamas, the embattled government of Bashar Al Assad of Syria, Iraqi Shiite militias, and rebels in Yemen and Bahrain. President Obama has asserted, both before and after the JPA was agreed, that the option of U.S. military action against Iran's nuclear facilities is available. However, further U.S.-or Israeli-discussion of military options against Iran is unlikely unless nuclear talks collapse outright. In line with a JPA provision that no new sanctions be imposed on Iran during the JPA period, the Administration has threatened to veto legislation, including S. 1881, that would add sanctions on Iran-even though sanctions provisions would take effect only after the JPA expires. Rouhani's unexpected election win-a result of a large turnout of reform-minded voters such as those who protested the 2009 election results-demonstrated strong support not only for reducing Iran's isolation but for domestic reform. Rouhani has sought to satisfy this constituency, in part by orchestrating the release of some political prisoners and easing some media restrictions. But, Iran's judiciary remains in the hands of hardliners who continue to restrict social freedoms and prosecute regime critics and dissenters. For further information, see CRS Report RS20871, Iran Sanctions, by Kenneth Katzman; and CRS Report R43333, Interim Agreement on Iran's Nuclear Program, by Kenneth Katzman and Paul K. Kerr.