"Iran's national security policy is the product of many, and sometimes competing, factors [...] Some experts assert that the goal of Iran's national security strategy is to overturn a power structure in the Middle East that Iran asserts favors the United States and its allies Israel, Saudi Arabia, and other Sunni Muslim Arab regimes. [...] Others interpret Iran as primarily attempting to protect itself from U.S. or other efforts to invade or intimidate it or to change its regime. Its strategy might, alternatively or additionally, represent an attempt to enhance Iran's international prestige or restore a sense of 'greatness' reminiscent of the ancient Persian empires. From 2010 until 2016, Iran's foreign policy also focused on attempting to mitigate the effects of international sanctions on Iran. Iran's national security policy focuses on the Near East region, including on U.S. operations, allies, and activities in that region. [...] Iran's foreign policy also seems to be directed at influencing the policies and actions of big powers, such as those in Europe as well as Russia, that are active in the Near East--either as partners or antagonists of U.S. interests in that region. [...] U.S. officials and U.S. reports assert that there has been no observable alteration of Iran's pursuit of its core regional activities [since the implementation of the Joint Comprehensive Plan of Action, or JCPOA]. To date, Iran has used the JCPOA to ease its international diplomatic isolation and to try to develop itself as a regional energy and trade hub and explore new weapons buys. "
CRS Report for Congress, R44017
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html