Since the Islamic Revolution in Iran in 1979, a priority of U.S. policy has been primarily to reduce the perceived threat posed by Iran to a broad range of U.S. interests, including the security of the Persian Gulf region. U.S. officials also express a broad range of concerns about Iran's human rights abuses. The implementation of a July 14, 2015, "Joint Comprehensive Plan of Action" (JCPOA) nuclear agreement between Iran and six negotiating powers appeared to represent an opportunity to reduce the long-standing U.S.-Iran enmity and construct a new relationship. During the 1980s and 1990s, U.S. officials identified Iran's support for militant Middle East groups as the primary threat posed by Iran to U.S. interests and allies. Iran's nuclear program took precedence in U.S. policy after 2002 as the program expanded and the chances that Iran could develop a nuclear weapon increased. In 2010, the United States orchestrated broad international economic pressure on Iran to persuade it to agree to strict limits on the program. The pressure might have contributed to the June 2013 election of the relatively moderate Hassan Rouhani as president of Iran, whose government subsequently negotiated a November 2013 interim nuclear agreement and then the JCPOA. The JCPOA, which began formal implementation on January 16, 2016, exchanged broad sanctions relief for nuclear program limits intended to give the international community confidence that Iran would require at least a year to produce a nuclear weapon if it decided to do so. President Obama has asserted that the JCPOA has the potential to produce the added benefit of improving U.S.-Iran relations. However, Iran has continued to test ballistic missiles, sought new conventional arms from Russia, maintained support for regional movements and factions such as Syrian President Bashar Al Assad and Lebanese Hezbollah, insisted on additional sanctions relief, arrested additional U.S.-Iran dual nationals, and threatened to close the Strait of Hormuz if Iran is attacked. These actions have prevented any broader rapprochement between Iran and the United States and Iran and the Arab states of the Gulf Cooperation Council (GCC: Saudi Arabia, Kuwait, UAE, Bahrain, Qatar, and Oman). The United States has long-standing and extensive security relationships with the GCC states that enable the United States to maintain about 35,000 military personnel at facilities throughout the Gulf. The United States has held two summit meetings with GCC leaders (May 13-14, 2015, and April 21, 2016) to try to reassure the GCC that Iran's regional influence can and will be contained, even though Iran has more financial resources at its disposal because of sanctions relief. At the meetings, President Obama has reaffirmed all aspects of U.S.-GCC security cooperation, including a commitment to continuing U.S. sales of arms. Domestically, Rouhani and the JCPOA appear to have broad support, but many Iranians say they also want greater freedoms of expression and assembly. Rouhani's public support was demonstrated by the strong showing of moderate conservative candidates in the elections for the parliament and a key clerical body, which were completed on April 29. The results appear to strengthen Rouhani but might still not render him able to limit hardliner control of the state institutions that curb dissent and free expression. The United States has supported programs to promote civil society in Iran, but successive U.S. administrations have stopped short of adopting policies that specifically seek to overthrow Iran's regime.