Today is the 30th anniversary of the beginning of the Iranian hostage crisis, America's first searing experience with Islamist terrorism.

On Nov. 4, 1979, Iranian militants seized the U.S. embassy in Tehran and took American diplomats as hostages. Fifty-two Americans were held captive for 444 days in a prolonged crisis that boosted the power of Iranian hardliners, torpedoed the Carter administration's ill-conceived efforts to engage Iran's revolutionary leaders, and ushered in an era of rising terrorism and regional instability in the Middle East.

The hostage crisis dramatically reshaped the politics of both countries. Many Americans remember that President Carter's mishandling of the hostage crisis was a major factor that contributed to his overwhelming defeat by Ronald Reagan in 1980. But few are aware of the momentous impact that the hostage crisis played in Iran's revolutionary politics.

Iran had been convulsed by the 1979 revolution against the Shah (King), Mohammed Reza Pahlavi. But the loose coalition of diverse political groups that coalesced to overthrow the Shah quickly splintered into rival factions that engaged in a bitter power struggle. A provisional government led by moderate leader Mehdi Bazargan presided over an increasingly polarized political environment in which secular nationalists steadily lost ground to leftists and to radical Islamists led by Ayatollah Ruhollah Khomeini.

The seizure of the U.S. embassy enabled Khomeini's hardline Islamists to hijack Iran's revolution, discredit the provisional government and outflank Iranian leftists by monopolizing the anti-American soapbox. It also helped them block any rapprochement between Iran and the United States, which Khomeini called the "Great Satan." Iran's Islamists knew that three previous Iranian revolutions had been aborted after westernized elements of the revolutionary coalition defected and cooperated with foreign powers. In the most recent case, an anti-Western government led by Mohammed Mossadegh was overthrown in 1953 by disaffected Iranians, supported by the CIA, who restored the young Shah to power.

Although the militants who seized the hostages demanded the return of the Shah to stand trial, their real goal was to block any improvement in relations with the United States, which they saw as a threat to the consolidation of their power within Iran. Three days before the hostages were seized, Premier Bazargan met with President Carter's National Security adviser, Zbigniew Brzezinski, in Algeria. The Carter administration was anxious to restore good relations with Iran and had soft-pedaled its criticism of growing human rights violations after the revolution.

But for Khomeini, any attempt to improve relations with the United States was intolerable, because the "Great Satan" would tempt westernized Iranian moderates to turn against his Islamist revolution. (Khomeini's successor, Ayatollah Ali Khamenei, continues to fear that today.)

On Nov. 1, 1979, Khomeini called for Iranian students to demonstrate in memory of the first anniversary of a bloody Nov. 4, 1978 protest against the Shah at the University of Tehran, noting that in the absence of the Shah, "all our problems come from America." In the course of that demonstration, hundreds of militants emerged from the crowd and seized the U.S. embassy. The American hostages became pawns in Iran's internal power struggle and enabled Khomeini's followers to bring down the provisional government and gain a stranglehold on Iranian politics.

The bewildered Carter administration, whose efforts to engage Iran's revolutionary leaders were violently rebuffed, badly mishandled the hostage crisis. Carter initially ruled out the use of force, which weakened his administration's bargaining power and strengthened the hand of the militants holding the hostages. Then his administration was lured into a series of negotiations with the Iranians in which it made concessions, such as agreeing to set up a U.N. commission to investigate American involvement in the crimes of the Shah, only to see the Iranians repeatedly renege on their promises.

Eventually, of course, the hostages were released minutes after Carter left office. Former Iranian President Abolhassan Bani Sadr later attributed this to a fear of incoming President Ronald Reagan.

Iran's Islamist hardliners learned a lesson from the hostage crisis: terrorism works. They later made terrorism a major part of their foreign policy and deployed Revolutionary Guards to export their violent revolution to other Muslim countries. In Lebanon, the Revolutionary Guards helped to create, arm and train Hezbollah ("Party of God") which kidnapped another 15 American hostages in the 1980s, some of which Iran traded for arms in the Iran-Contra affair.

Today President Mahmoud Ahmadinejad, who rose out of the Revolutionary Guards, increasingly depends on intimidation and terrorism to stay in power. His regime has called for demonstrations in front of the former U.S. embassy, but has warned Iran's opposition movement to stay off the streets. -- But at least some in the crowd are expected to protest against Ahmadinejad's regime instead of chanting "Death to America." They know that the Iranian people are now hostages to the extremist goals of Iran's bankrupt revolution.

James Phillips is Senior Research Fellow for Middle Eastern Affairs in the Douglas and Sarah Allison Center for Foreign Policy Studies, a division of the Kathryn and Shelby Cullom Davis Institute for International Studies, at The Heritage Foundation.