On May 8, 2018, President Donald Trump signed National Security Presidential Memorandum 11, "ceasing U.S. participation in the JCPOA [Joint Comprehensive Plan of Action] and taking additional action to counter Iran's malign influence and deny Iran all paths to a nuclear weapon." The action sets in motion a reestablishment of U.S. unilateral economic sanctions that will affect U.S. businesses and include secondary sanctions that target the commerce originating in other countries that engage in trade with and investment in Iran. Prior to this juncture, the United States had led the international community in imposing economic sanctions on Iran in an effort to change the government of that country's support of acts of international terrorism, poor human rights record, weapons and missile development and acquisition, role in regional instability, and development of a nuclear program. The United States' abrogation of its participation in the JCPOA, at least in the near-term, sets the United States apart from its allies and partners in what has been for more than a decade a unified, multilateral approach to Iran's malign activities. This report identifies the basis in U.S. law for sanctions imposed on Iran, and the nature of the authority to waive or lift those restrictions. It comprises four tables that present legislation and executive orders that are specific to Iran and its objectionable activities in the areas of terrorism, human rights, and weapons proliferation. It will be updated if and when new legislation is enacted, or, in the case of executive orders, if and when the President takes additional steps to change U.S. policy toward Iran. On July 14, 2015, the United States, China, France, Germany, the Russian Federation, the United Kingdom, European Union, and Iran agreed to a Joint Comprehensive Plan of Action to "ensure that Iran's nuclear programme will be exclusively peaceful.... " In turn, the negotiating parties and United Nations would "produce the comprehensive lifting of all U.N. Security Council sanctions as well as multilateral and national sanctions related to Iran's nuclear programme, including steps on access in areas of trade, technology, finance, and energy." On January 16, 2016, the International Atomic Energy Agency verified that Iran had implemented the measures enumerated in the JCPOA to disable and end its nuclear-related capabilities. Secretary of State Kerry confirmed the arrival of Implementation Day (defined in Annex V of the JCPOA). President Obama, the State Department, and the Department of the Treasury's Office of Foreign Assets Control initiated steps for the United States to meet its obligations under the JCPOA (Annexes II and V)-revoking a number of executive orders, delisting individuals and entities designated as Specially Designated Nationals, issuing general licenses to authorize the resumption of some trade, and exercising waivers for non-U.S. persons as allowable by various laws. President Trump's May 8 announcement indicates that the United States will, over the next three to six months, reconstruct the U.S. sanctions regime.