Fear of an Iranian nuclear weapon predates Iran's 1979 Islamic revolution, when the pro-West Shah Mohammad Reza Pahlavi was deep in negotiations with the US, France and West Germany, on a nuclear-energy spending spree that was to yield 20 reactors.
Late 1970s: US receives intelligence that the Shah had "set up a clandestine nuclear weapons development program."
1979: Shah ousted in the Iranian revolution, ushering in the Islamic Republic. After the overthrow of the Shah, the US stopped supplying highly enriched uranium (HEU) to Iran. The revolutionary government guided by Ayatollah Ruhollah Khomeini condemned nuclear weapons and energy, and for a time stopped all projects.
1984: Soon after West German engineers visit the unfinished Bushehr nuclear reactor, Jane's Defence Weekly quotes West German intelligence sources saying that Iran's production of a bomb "is entering its final stages." US Senator Alan Cranston claims Iran is seven years away from making a weapon.