By Sadeq Saba
BBC regional analyst
Visitors to Iran these days can't fail to notice a change in the atmosphere of the place.
Twenty-five years on from the Islamic revolution, young girls on the streets of Tehran have abandoned their black chadors in favour of tight-fitting coats and designer sunglasses.
Close-fitting coats are replacing the black chador
Few government agents seem inclined to enforce the Islamic Republic's moral code any more.
Iran Air no longer warns passengers flying into Tehran about the need to adhere to a strict dress code.
Restaurants have started admitting women who are "improperly" dressed and alcoholic drinks are readily available on the black market.
In recent months, ecstasy tablets have also become popular with the young. Men and women now mix together more freely than ever before.
Teenagers pack into Western-style coffee shops in the evenings, and sex before marriage is becoming more acceptable.
There has also been a radical change in the political atmosphere.
Six years after President Khatami swept to power in a landslide election victory, there is a widespread feeling of disillusionment with the reformist cause.
Young voters were key to Khatami's election in 1998
The frustration is particularly evident amongst young Iranians, who make up more than two-thirds of the population.
Most despise the Islamic regime but are no longer prepared to risk violence to change it. They are content to get what enjoyment they can from life and to keep out of the way.
For the conservatives - who never had much support from the country's youth at election time - this mood does them no damage.
But for the reformists, outraged by the disqualification of hundreds of their candidates for parliamentary elections in February, political indifference is poison.
President Khatami's victory six years ago was achieved mainly because his ideas mobilised younger voters.
Young people are no longer prepared to risk violent protest
Now, however, not even the imprisonment of reformist politicians or banning of liberal newspapers mobilises them. They see the reformists as part of the Islamic establishment and have little sympathy for them.
Many people say they are not planning to vote in the elections, because it will not make any difference to the ruling clerics anyway. So turn-out is expected to be low, which will only help the conservatives.
Unlike their counterparts in the rest of the Middle East, many young Iranians are openly pro-American, and approve of the American lifestyle.
Secularism is now becoming one of the main demands in Iran. The country where the idea of political Islam was born has become the place where it is slowly dying.
It is not just ordinary Iranians who are saying that the mullahs should return to the mosques. Some mullahs, too, have concluded that it would be better for their faith if religion kept out of politics.
These issues, remarkably, are debated openly in Iran, even within the clerical establishment.
This new openness has been the hallmark of the years since President Khatami came to power.
Many newspapers have started up and then been closed by the conservative authorities. But the momentum for debate has not been stopped.
The biggest growth area has been the internet and interest in the international media.
Although in theory watching satellite television is forbidden, it is very largely tolerated.
The Iranian supreme leader, Ayatollah Ali Khamenei, is now the principal target of popular resentment.
He is seen as the main obstacle to democracy and freedom in Iran.
During recent demonstrations, some people dared for the first time to denounce him personally.
Alcohol is readily available on the black market
However, a well-organised minority still support the ayatollah and see him as a sacred leader whose orders should be obeyed without question.
A small group of extremists among them attack critics of the regime and disrupt meetings in the name of defending the supreme leader and Islamic values.
Another big change in Iran is the increasingly assertive and visible role of women in society.
For the first time in Iranian history, over 60% of new entrants to universities are women. Women are now at the forefront of calls for reform and for greater social freedom.
But despite the general lightening up of the atmosphere, the law remains the same.
Restaurants can still be closed for allowing un-Islamic behaviour, people caught drinking can still face a flogging, and hardliners still intimidate women who are deemed to be improperly dressed.
While many Iranian people, especially women, say they have forced the ruling clerics to accept that change is a reality, others think that the regime's tolerance of more individual freedoms is part of a long-term plan.
Conservative leaders, they believe, would like to follow a so-called Chinese model of society, where there is relative individual freedom but tight political control.
Nobel winner Shirin Ebadi - one of many women calling for reform
The still-powerful former president, Akbar Hashemi-Rafsanjani, has said that he favours such a model.
But there is a limit to what the ruling clerics will tolerate.
Devout Muslims see hejab as the symbol of Islam and would never accept a freer dress code for women.
Opinions are divided as to what impact a conservative victory would be likely to have.
The conservatives may tolerate greater social freedoms in order to appease the public, although this could incense the more traditional clerics.
But a low turn-out in the elections would ultimately damage the legitimacy of the regime.
Whatever the outcome of the elections, the general consensus in Iran is that the ruling clerics are no longer in a position to disregard public opinion.
The political agenda in Iran has certainly changed - democracy and human rights are now at the core of popular aspirations.
It would be very difficult for anyone to turn the clock back now.