The Islamic Republic of Iran was established 30 years ago. That black day in history should, perhaps, have been marked last month; for in January 1979, after a year of demonstrations by his Islamist opponents, the shah - sick with cancer and abandoned by the Carter administration - left Teheran for exile. Arguably, this month is the proper anniversary because it was in February 1979 that the Iranian military stood down and Ayatollah Ruhollah Khomeini ended his exile, returning from Paris to a tumultuous Teheran welcome. As he was helped down the steps of the plane, Khomeini showed nary a flicker of emotion. He went directly to a cemetery where his "martyred" followers were buried. Millions clogged the route to get a glimpse of the 76-year-old cleric; it took three hours to make the 40-km. journey. Shapur Bakhtiar, the interim prime minister appointed by the shah, said Khomeini was welcome but would have to respect the rule of law. Khomeini ordered him to resign. He went into exile. In 1991, Khomeini had him killed by Hizbullah. Sixteen days after Khomeini's triumphant arrival, PLO chief Yasser Arafat became the first foreign visitor to pay him homage. The two men held hands; Arafat beamed and snuggled ever closer to Khomeini, whose revolutionary guards had been trained in PLO camps in Lebanon. When the cameras left, Khomeini lectured Arafat on the need to drop his nationalist facade and make the Palestinian struggle against Israel part of the larger worldwide jihad. And on February 17, he turned the former Israeli embassy in Teheran over to Arafat. It took Khomeini a while to pacify all of Iran. A revolt by the Turkomans had to be put down; former generals and officials loyal to the shah had to be executed. And over the coming years the revolution would consume its own. Revolutionary committees were established to purge the government and military of bourgeois supporters whose religiosity was suspect. Khomeini ordered thousands of executions. Well into the late 1980s and beyond, there were always new internal enemies to slaughter. Some say that the true anniversary of the Iranian revolution should be marked on April 1 when, after a nationwide referendum, Khomeini proclaimed the Islamic Republic. IRAN'S FALL into the benighted hands of Shi'ite extremists turned out to be a geo-strategic blow of historic proportions to Western interests. The mullahs not only created a theocracy at home, they exported their pernicious fanaticism abroad. The November 4, 1979 takeover of the US embassy, and the 444-day hostage crisis, profoundly undermined customary international law. A share of the country's vast oil wealth has been put at the disposal of its imperial goals - endowing the regime's quest to build a nuclear bomb, funding terrorist movements and establishing proxies such as Hizbullah. American policymakers misjudged Iran's willingness to behave pragmatically in what came to be known as the Iran-Contra affair. In 1985, the Reagan administration secretly sold Iran $30 million worth of weapons to defend itself against Iraqi aggression, in the hope that a new leaf could be turned over in relations between the two countries - and as ransom for US hostages held by Iran's Lebanese allies. Rather than warn the US away from such folly, Israel played an instrumental role in facilitating the scheme because Jerusalem also misjudged the depth of the mullahs' intransigence and loathing of the "infidels." Khomeini died in 1989 and was replaced by Ayatollah Ali Khamenei, who now controls the ruling 12-man Council of Guardians. On Monday, when Iran launched into orbit its first domestically made satellite - reportedly a civilian version of the Shihab 3 ballistic missile - the supreme leader obtained further, tangible proof that international sanctions are little more than a nuisance to Iran's imperial aspirations. PRESIDENT Barack Obama says that if Iran is willing to unclench its fist, it "will find an extended hand from us." But the mullahs are playing hard to get. Today, diplomats from the US, Russia, Britain, France, Germany and China are scheduled to meet in Frankfurt to discuss Iran's drive for nuclear weapons. The US needs to convince them that - whatever the new administration's tactical differences from the previous one - Washington will not tolerate a nuclear-armed Iran.