The latest student protests in the Iranian capital, Tehran, have quickened the collective pulse in Washington among those eagerly awaiting "regime change" in the Islamic republic.

President Bush has welcomed what he called popular demands for a "free Iran." Administration officials and their neoconservative allies have proclaimed that the Iranian people are at last acting on their calls to overthrow the ruling mullahs. Switch on CNN or Fox News and listen to Iranian exiles gleefully declare that the collapse of clerical power could be only months away.

But is Iran, once the center of radical Islam, really ripe for another revolution? Has it reached what Secretary of Defense Donald Rumsfeld likes to call a "tipping point," ready to fall with the slightest push? Neither history nor contemporary facts on the ground support such conclusions.

In marked contrast to the run-up to the 1979 Islamic Revolution, the fruit of what has been called a "theology of discontent" created over many decades by disparate factions, politics in Iran today remains very much the preserve of a narrow circle of "insiders." These revolutionaries, comprising so-called reformers and hard-liners alike, have no intention of easing their shared monopoly on power.

The result is the complete lack of any credible opposition political movement or cohesive ideological challenge to the current Islamic political system. Restive students, often identified by the Bush administration as those who might lead an internal rebellion, remain few and have repeatedly failed to turn their street demonstrations into a broad-based opposition movement. Simply put, there is no viable alternative on the horizon.

At the same time, Iran's constitution concentrates enormous power in the hands of the supreme clerical leader, appointed by conservative clerics. This includes command of the armed forces, control over the secret police and the courts, and the authority to confirm or reject the election of the president.

Backed by such institutional authority, and able to call on legions of Islamic vigilantes and other supporters sworn to uphold absolute clerical rule, supreme leader Ayatollah Ali Khamenei has little to fear from the Iranian "street." Militant hard-liners recently burst into a university dormitory and beat students as they slept.

The beatings were a repeat of 1999, when foot soldiers of Khamenei rampaged through a student hostel, igniting five days of protests in which thousands of students nationwide staged the largest demonstrations since the 1979 revolution. The ease with which those 1999 protests were suppressed and the brutality of the subsequent repression have helped ensure any threat will remain in the background for years to come.

The "pact" the Bush administration and its allies in Congress claim to have established with the disenchanted Iranian nation against its own leaders is a pure fabrication, one that plays into the hands of clerical hard-liners by allowing them to paint their opponents as U.S. stooges.

Iranians do want change, but the point on which most agree is that fundamental reform must come about peacefully and without U.S. interference. Besides, it is certain that whatever might emerge in a post-clerical Iran would not resemble a Western-style, secular democracy but would instead take into account Iranians' deeply felt commitment to Islam.

Last summer the White House publicly abandoned any hopes for Iran's official reform movement, led by President Mohammad Khatami, and called on the Iranian people to push for political and social change on their own. With nothing to show for the intervening months, the administration is now groping toward a new strategy to be encompassed in what is known as a "national security directive."

The document, now circulating in competing drafts, is classified, but there are worrisome signs it will draw heavily on the experience of the unfinished Iraq campaign and will likewise rely on a coalition of Washington hawks and exiles to see it through.

Already, the familiar refrain can be heard from administration figures: intimations of high-level Iranian complicity with al Qaeda; the development of weapons of mass destruction outside international safeguards; and reassuring strains from the expatriate elite that disgruntled Iranians would welcome U.S.-inspired "regime change" with open arms.

U.S. officials now speak openly of deploying the armed Iranian opposition, allied with Saddam Hussein until his fall and listed by the State Department as a terrorist group, to pressure the Iranians. The son of the disgraced shah, who has no backing at home but enjoys the support of many in the diaspora and among Washington hawks, is already positioning himself for power.

If the chaos of postwar Iraq is not lesson enough, the administration would do well to ponder past experience with U.S.-led "regime change" in Iran; it is a sorry one, and there is nothing to suggest that things would be different this time. The CIA-inspired coup that ousted the elected government and restored the late shah to power in 1953 planted the seeds of the Islamic Revolution 25 years later, inflicting one of the greatest setbacks in U.S. diplomatic history.

It is likely a similar backlash could occur if the United States intervened once again in Iran.