TEHRAN, Iran — One year ago, after a disputed presidential election, Iranians exploded in the most intense and sustained protests their country had known since the Islamic Revolution of the 1970s. Calm has now returned to Iran. Nothing has changed — but everything has changed.

The religious regime remains in power and faces no imminent threat. Protests flare up from time to time — several are planned for this weekend — but no momentum gathers behind them. Thousands of protesters were arrested after last year's demonstrations. Eighty-one were released last week, but they are liable to be re-arrested if they resume political activity. The regime has succeeded in intimidating its opponents.

Yet a recent two-week trip through Iran, during which I spoke to dozens of ordinary people, suggested that last year's outburst of protest changed something deep. The regime has lost an important measure of legitimacy. Most Iranians are young; an astonishing 70 percent are under 30. Last year's trauma has disillusioned many of them. They pose a serious long-term threat to the Islamic Republic.

“Right now, people are afraid,” one young man told me. “But remember, we are the people who got rid of Alexander, Genghis Khan and Tamerlane.”

Last year's protests began after the June 12 presidential election. The result was surprisingly decisive — a landslide victory for the incumbent, Mahmoud Ahmadinejad — but what angered people more was that it was announced within hours after polls closed, before many ballots could have been counted. Then the Supreme Leader, Ayatollah Ali Khamenei, endorsed the result and demanded that protests end. This was a fateful turning point.

Until that moment, many Iranians still saw the Supreme Leader as a figure above factions and open, if not to all, at least to a spectrum of respectful opinion. By siding so decisively in favor of Ahmadinejad, and scorning the protesters so sharply, Khamenei lost that aura of impartiality. He is now a clear partisan of one faction. This removes a key pillar of the regime's stability. No neutral figure remains who commands broad respect.

A breach has opened in Iranian society that is not likely to heal. When the Islamic Republic eventually falls or changes, historians will look back to 2009 as the moment when the tide began turning against it.

My trip, though, also showed me that despite last year's political turmoil and growing international pressure due to the escalating nuclear crisis, daily life in Iran is normal. There is no fear or tension in the air. Many Iranians with whom I discussed politics told me that change will come, but slowly. In a country with 25 centuries of history, this seems a natural attitude.

Iran's regime controls the instruments of power and coercion. Life is bearable for almost everyone, and pretty good for many. Under these circumstances, Iranians do not consider a possibly stolen election sufficient reason to rebel.

No people on earth understand the risk of violent revolution better than Iranians. In the 1970s they banded together to overthrow the Shah's dictatorship, certain that the next regime would be better. They wound up with one that is by most standards worse. This bitter experience was deeply traumatic. Because of it, many Iranians instinctively prefer to bear the ills they have than fly to others that they know not of.

Although the Green Movement, as last year's protesters called themselves, electrified the world, it may not have represented a majority of Iranians. In many parts of the country, people are pious and religious power is strong. The Green Movement has not managed to broaden its social base — a key difference from the anti-Shah protests of the 1970s, which found support at nearly every level of Iranian society.

The movement's goals are diffuse. It has not even managed to come up with a clear answer to the most basic political question: Should the Islamic system be reformed or abolished? Instead it has pushed two demands, free elections and rule of law. These are eminently reasonable, but not enough to bring Iranians charging out of their homes to face police and armed thugs.

The Green Movement has not been able to capitalize on last year's success. Protesters have failed to build a durable mass movement. Repression has been effective. Iran is not on the brink of exploding.

This poses an intriguing challenge to the U.S. and other Western countries. If the current regime in this important country is going to be in power for at least some years, might it not make sense to engage its leaders in dialogue, rather than pursue a policy of threats and sanctions?

“The history of my country shows that Iran has always wanted to be integrated with the world,” a college student told me in the town of Mahan, “and that is what we want now.”

Although the regime managed to crush last year's challenge, it emerged from the confrontation palpably weaker. Iranians are more deeply divided than at any time since the 1979 revolution. Rival factions have emerged in the ruling group. Pressure from the United States and Europe is intensifying, with a new round of United Nations sanctions on the horizon. The economy is not producing nearly enough jobs for an increasingly alienated young generation. Social ills are spreading. This does not bode well for the Islamic Republic.

The world was shocked by the brutality with which security forces in Iran suppressed last year's protests. Even more impressive, though, were the protests themselves. At great personal risk and with remarkable discipline, millions of courageous Iranians marched to demand their democratic rights. This would have been unthinkable in most Middle Eastern countries. There are seldom post-election protests in Egypt, for example, because Egyptians expect elections to be stolen; there are none in Saudi Arabia because there are no national elections at all.

This outburst of protest was the legacy of more than a century of progress toward democracy in Iran. Since the Constitutional Revolution of 1906, many Iranians have embraced democracy as a personal choice, not as something imposed on them by foreigners at the point of a gun. At mid-century they nearly succeeded in consolidating a democratic regime. After Prime Minister Mohammad Mossadegh nationalized Iran's oil, however, the British and Americans organized a coup to depose him.

Iran's modern history offers three alternative forms of government: democracy, monarchy and religious rule. Mossadegh was the last exemplar of democracy. His overthrow in 1953 was followed by a quarter-century of royal dictatorship. Then came more than three decades of theocracy. If the cycle continues, democracy is due for another turn.

Iran has the potential to become one of the world's most democratic Muslim countries, perhaps joining a list that includes Indonesia and Turkey among others. Over generations, its people have internalized the meaning of elections, parliaments and political debate. Last year's protests showed the vibrancy of Iran's long-suppressed democratic consciousness.

The challenge for Iran is how to get from here — an increasingly repressive state — to there: a more democratic regime. Last year the Green Movement fired a powerful salvo, then was beaten back. The unfolding of Iranian political history, however, has not ended. This story is not over.

Stephen Kinzer recently completed a two-week trip in Iran, where he researched this article. He wrote the piece from his home in Massachusetts. Kinzer is the author of numerous books, including "Reset: Iran, Turkey and America's Future," "Overthrow" and "All the Shah's Men."