Which did President Carter fail to do?

promote détente with Communist countries

create a peace agreement between Israel and Egypt

free Americans taken hostage by Iran

take action against the Soviet invasion of Afghanistan

free Americans taken hostage by Iran

What did President Carter fail to do?

- - free Americans taken hostage by Iran

President Jimmy Carter's failure to get the hostages back ruined his re-election chance in 1980. We might also note that the taking of the hostages was itself an action aimed at President Carter. The Iranian Revolution had ousted the shah of Iran, a US-backed leader. The former shah, Mohammad Reza Pahlavi, living in exile in Mexico, was found to have cancer, President Carter allowed him to come to the United States for treatment. This enraged the Iranians, who thought that the US was perhaps trying to bring the shah back to power. That's when the hostages were taken.