The consequences for the United States of the Iranian revolution were not limited to higher oil prices. Since 1945, the United States had expressed strong interest in this oil-rich country, opposing Soviet efforts to gain a position there in 1945–1946 and opposing also the nationalization of the Iranian oil industry under the leadership of Prime Minister Mohammed Mossadegh in 1951–1953. After contributing to the overthrow of Mossadegh and obtaining access to Iranian oil for American companies, the American government supplied large amounts of aid to the shah, Mohammed Reza Pahlavi, and to his efforts to westernize the country and make it a military power. Those efforts aroused the ire of the Muslim clergy, and the oppressiveness of the shah's regime generated opposition from others. Revolts erupted and gained strength during 1978, forcing the shah to flee early the following year and leading to the establishment of the Islamic Republic of Iran under the leadership of a Shiite Muslim leader, Ayatollah Ruholla Khomeini, who was determined that Islam, not Western influences, should reign in Iran. On 4 November 1979, shortly after the shah entered a New York hospital for treatment of cancer, several thousand Iranian youths seized the American embassy in Teheran and took most members of the staff hostage, demanding that the United States return the shah.
Carter faced another enormously difficult problem. He tried to free the hostages without taking military action, relying chiefly on diplomatic and economic pressures, including the freezing of Iranian assets in the United States. He obtained help from others, such as United Nations Secretary General Kurt Waldheim. Thirteen female and black staff members were released shortly after they had been seized, but the others remained captive. In April 1980 a frustrated president broke with past policy and (over the opposition of Secretary Vance) authorized a military rescue operation. It had to be aborted, however, when three of the eight helicopters involved developed mechanical problems, and, in pulling out, one of the helicopters collided with a transport plane, killing eight men and injuring others. The captors released an ill hostage in July, and the Iranian government, now suffering an invasion from Iraq, soon announced conditions for the release of the remaining fiftytwo, but more weeks would pass before they were free.