The Islamic Association, a national student organization, is not quite what its name suggests.

"No organization can operate in this country without putting `Islamic' in its name," snorts the elected leader of one association chapter, before launching a group discussion about dismantling theocracy established by the 1979 Islamic revolution.

The tension pitting official Iran against the kind of society in which most Iranians want to live cuts through all aspects of life here, erupting regularly into violence.

The latest outburst has been playing out in downtown Tehran for nearly a week, with nightly violent clashes between those seeking greater freedom and those bent on maintaining the government.

The demonstrations continued tonight, although they were more subdued than the ones late last week.

The government, which on Saturday blamed "thugs and hooligans" for fomenting the violence, has begun arresting students and their supporters.

The unrest does not appear to be over. Today, President Bush ( news -web sites ), in Kennebunkport, Me., lent his support to the demonstrators, saying, "This is the beginning of people expressing themselves toward a free Iran which I think is positive."

In Iran today, several hundred dissident intellectuals, including several clerics, issued a statement supporting the right of Iranians to criticize their government. Further, the statement denounced as "heresy" the possession of absolute power a reference to Iran's supreme leader, Ayatollah Ali Khamenei.

Finally, the Iranian Student News Agency reported that students planned to hold their first daytime demonstration at noon Monday in downtown Tehran.

The week's protests highlight the question of how long a group of aging clerics can impose their vision of an Islamic state on a nation 70 percent of whose people are under 30.

While some Iranians still believe in their theocracy, the majority want a sweeping transformation. They do not want to be told what to think, what to wear, what to read, what to watch and how to behave, and they are frustrated at the glacial pace of change.

Still, the demonstrations do not really pose a serious challenge to the mullahs, because opponents of the system lack a unifying figure or organization that can translate their demands into public pressure.

They thought they had found their champion in President Mohammed Khatami, but calls for his resignation along with cries of "Kill all the mullahs!" during the protests showed how disillusioned his former supporters have become, how angry that their votes made so little difference.

"Six years ago everyone was persuaded that the Islamic Republic could stay and Mr. Khatami as a clergyman could be president and we needed some changes like freedom of speech," said Mohsen Sazegara, a former aide to Ayatollah Khomeini and a reformist journalist, speaking before he was detained today with his son on charges of incitement.

"Now day by day people are becoming more radical in their demands," he added. "People are saying everything must be changed."

But there is no collective vision of a viable alternative. "The problem with reforms is that Iranians know what they don't want, but they do not know what they want," said Muhammad, a 24-year-old student. Many students interviewed did not want their full names or schools published, saying they feared subsequent harassment.

Mostly, young people here want the government to stop interfering in their day-to-day lives.

Faruda, a 20-year-old math major at an Isfahan university, was told to report to the campus morals committee last month.

"They said I was talking to men too much," she said, and that her clothing was immodest.

They lectured her for three hours, Faruda said, handing her a list of 13 verses to read from the Koran about proper women's dress. "I just listened; you can't argue back because it's the Koran," she said.

Men get into similar trouble. Students at the same university said a male student was cursed as an infidel and beaten by members of Baseej, a paramilitary government organization whose older members are the shock troops used to put down student demonstrations. His infraction? Walking down the dormitory corridor in his underwear.

Reformists point out that students in Tehran can hold hands in public now, but in the provinces even that liberty is denied.

"It takes a lot of courage just to walk with a woman down the main street of Isfahan," said Payam, a 21-year-old with the shoulder-length hair that many male students grow as a form of protest.

"We don't want a government that prescribes to us all the time what is good and what is bad," he added.

Activist students are struck by the fact that the revolution puts great emphasis on education, then seeks to veil their minds.

"We should be able to criticize the government, the religion," said Hamed, a 21-year-old engineering major. "If we want to be able to understand it, we should be able to criticize it."

Students concede that they are given far more leeway than society in general. Student journals published articles backing the American invasion of Iraq, for example, something impossible in the country at large.

But its the lack of change in society in general that grates on many.

Take this spring's mysterious ban on manteaux the coats women are supposed to wear in public. Their hemlines have been creeping steadily upward, to the point that they come much closer to long shirts than the black cloaks considered the ideal revolutionary hejab.

Suddenly in May all the manteaux shops in Tehran got a warning to stop selling short coats.

"Recently the improper Islamic hejab of some women in the city has caused certain worries and social abnormalities," the letter began, warning store owners not to sell anything tight-fitting, above the knee or with slits.

The offending item disappeared from store windows, and many women stopped wearing the short pink or white cloaks, even though government agencies contacted by the Iranian press denied sending the letter.

"We shouldn't listen, but we get scared, so you see a lot of women wearing darker colors these days," said Aliyeh Almoodayee, a 21-year-old graphics art student.

Abdollah Ramezanzadeh, the spokesman for President Khatami, said: "They want to create the perception of fear. They are trying to do something to say they are powerful, but they cannot make real problems for people anymore."

Reformists believe that, with 48 million Iranians under 30, time is their ally. Change must come eventually.

There are, of course, those who support crackdowns.

"Times are hard so young men have trouble getting married," said Fatimeh Ahmedi, a 40-year-old mother. "The freer women become the more men would be tempted to get involved in immoral acts."

Such sentiments find their echoes among conservative students and others. In the office of the Islamic Students Society, the conservative counterpart of the Islamic Association, portraits of the late revolutionary patriarch Ayatollah Ruhollah Khomeini stare down from the wall in every room and his thoughts dominate the conversation.

"We have an ideology in this country and it forms the center of all our dialogues," said Majdodin Muallimi, the secretary general of the society. "What is more important than anything to us is our religion, our faith and our ideology."

Mr. Muallimi and others like him admit that the Islamic revolution has failed to get rid of government corruption or to create economic growth, as it promised to do, but they argue that Iranians still support the system. They point to the 80 percent participation of people in the last presidential election as proof.

Former stalwart supporters of the revolution like Hassan, a 65-year-old retiree from a government enterprise ( news -web sites ) in Isfahan, are tired of their votes being thus misrepresented. That is something Hassan would like to change.

"The day the shah left the country was the happiest day of my life," he said. "But these have become the worst days whatever they promised the revolution would bring was a lie. Unemployment is high, inflation is bad, the economy is bad, the society is full of addicts."

He and his wife and children joined millions who did not cast ballots in the February elections for municipal councils. Turnout in major cities hovered around 10 percent.

"The political clerics took our participation as a approval for the system as a whole," said Hassan, adding that the clerics exploit religion just to hang onto power. "So we decided not to go do any of that anymore."

Despite their rancor, Hassan and many of the students disagree with those, and there are some, who would like to see the United States force a change of government, as it did in Iraq.

They were dismayed by President Bush's praise of the demonstrations, believing that many Iranians will see his words as foreign meddling, strengthening the conservatives. Indeed, both the leadership and the press loyal to it have portrayed the students and their supporters as the paid tools of the United States.

They said that many people went into the streets at the behest of monarchist television stations, based in California and broadcasting to Iran via satellite. Those people, the government said, want the shah's son returned to power, a view most Iranians considered a joke.

Far better, many students and men like Hassan say, to leave the process of developing a democracy to the Iranians themselves.

"We were taught to accept everything, not to ask why," Hassan said. "Change will come with the new generation when we are all gone. Change will come with my grandsons, because they ask why about everything."