On Feb. 14, 1979, less than one month after the shah of Iran’s exile, the U.S. Embassy in Tehran was overrun by Iranian militants. Within hours, it was returned to U.S. hands. Now on notice that our diplomats were stationed on a vulnerable outpost in a sea of anti-Americanism, the Carter administration considered, but rejected, closing the embassy. In October, President Carter permitted the shah – despised by Iranians and the regime that replaced his – to enter the United States. Days later, Iranians climbed the embassy gates again, took the Americans there hostage and demanded the shah’s return, beginning...