From the Overview: "Sanctions have been a significant component of U.S. Iran policy since Iran's 1979 Islamic Revolution that toppled the Shah of Iran, a U.S. ally. In the 1980s and 1990s, U.S. sanctions were intended to try to compel Iran to cease supporting acts of terrorism and to limit Iran's strategic power in the Middle East more generally. After the mid-2000s, U.S. and international sanctions focused largely on trying to persuade Iran to agree to limits to its nuclear program. Still, sanctions have had multiple objectives and sought to address multiple threats from Iran simultaneously. This report analyzes U.S. and international sanctions against Iran. CRS [Congressional Research Service] cannot independently corroborate whether any individual or other entity might be in violation of U.S. or international sanctions against Iran. The report tracks implementation of the various U.S. laws and executive orders, some of which require the blocking of U.S.-based property of sanctioned entities. No information has been released from the executive branch indicating the extent, if any, to which any such property is currently blocked. The sections below are grouped by function, in the chronological order in which these themes have emerged."
CRS Report for Congress, RS20871
Congressional Research Service: https://crsreports.congress.gov/