The ongoing conflict between Iran's rulers and the Iranian public is the result of a head-on collision between two contradictory forces. In recent years, public attitudes in Iran have become more liberal. At the same time, power has shifted from conservative pragmatism toward a much more militant fundamentalism. The call by the most important group of Iran's clerics for the election results to be thrown out is but the latest sign of the fight back of both the reformist and pragmatic conservative factions.

Thirty years after the Islamic revolution, Iranians are growing demonstrably less religious and more liberal. Two face-to-face surveys of more than 2,500 Iranian adults, conducted in 2000 and 2005, clearly show the trend. The percentage of those who "strongly agree" that democracy is the best form of government increased from 20 per cent to 31 per cent.

Similarly, on a number of questions concerning gender equality - including political leadership, equal access to higher education, and wifely obedience - the numbers continued a downward trend. Those who considered love as the basis for marriage increased from 49 per cent to 69 per cent, while those who depended on parental approval fell from 41 per cent to 24 per cent. In 2005, a much higher percentage than in 2000 defined themselves as "Iranian, above all" rather than "Muslim, above all".

This trend is not hard to understand. The imposition of a monolithic religious discourse on society has made liberal values attractive to Iranians. But, while this was reflected in reformist trends in the country's wider political life, a movement toward militant fundamentalism took shape within the regime's power structure. Reform-minded politicians were partly to blame for this change. Far from opposing absolutist power as an impediment to religious democracy, they tried to persuade the Supreme Leader, Ayatollah Ali Khamenei, of the value of reform.

But Mr Khamenei had no interest in reform, as he made plain in dismantling the reform movement. The Presidency of Mohammad Khatami, an avowed reformer, who served eight years, beginning in 1997, convinced the supreme leader that his authority would be assured only if the presidency was held by a subservient fundamentalist such as the current President, Mahmoud Ahmadinejad.

In this, Mr K hamenei was following the lead of the late Shah, who kept Amir Abbas Hoveyda, a loyal retainer, as prime minister from 1965 until the Shah was overthrown in 1979.

The problem with the supreme leader's calculation, however, is that Mr Ahmadinejad is a loose cannon. His populist rhetoric and religious fundamentalism have alienated a large section of conservative-pragmatist clerics and their supporters.

Many members of this group honour the institution of private property, and Mr Ahmadinejad's talk of redistributing wealth is not to their liking. More disturbing to them is his apocalyptic conviction regarding the imminent advent of the Hidden Imam, the Mahdi, whose appearance is believed to lead to the destruction of the world and the end of time. Generally, Mr Ahmadinejad begins his public speeches with prayers for the Mahdi's immediate return.

For the Shia religious hierarchy, long accustomed to relegating the advent of the Mahdi to a distant future, Mr Ahmadinejad's insistent millenarianism is troublesome. They have often dismissed as unorthodox, if not heretical, any claim of personal contact with the Imam or speculation about his arrival. Several ayatollahs opined that such talk about the Mahdi is unbecoming of a president or, worse, indicative of an unstable leader.

These concerns were reflected in the fact that the Society of Combatant Clergy, a conservative body, was unable to endorse Mr Ahmadinejad's candidacy.

Defiance of the supreme leader by millions of Iranians just a day after he firmly endorsed Mr Ahmadinejad threw the country into a political crisis. Worldwide broadcasts of the beating and killing of protesters have undermined the regime's religious credentials.

Seeking a way out of this difficult situation, the supreme leader declared that the electoral disputes must be settled in through legal channels, not on the street.

Given his role in justifying electoral fraud, this argument seems like an effort to buy time to clear the streets of demonstrators, put opposition leaders under severe physical and psychological stress, and isolate Mir Hossein Mousavi, the presumed winner of the real vote.

Nonetheless, Mr Khamenei's invocation of the law echoes the demands of many conservative-pragmatists who lean towards Mr Mousavi, who is not in a position to challenge Mr Khamenei's authority directly.

Mr Mousavi must carefully continue his legal campaign, without compromising the trust he has gained from the majority of Iranians.

He must stand by his two principal demands: nullification of the election and establishment of an impartial committee to rule on the government's violations of the electoral law.

Should Mr Mousavi persuade Mr Khamenei to reconsider his position, the supreme leader's hold on power will be shaken. If Mr Khamenei holds fast, Mr Mousavi cannot gain the Presidency, but he will continue to represent the hopes of the majority of Iranians who differ dramatically with their government. For now, what will happen depends on Mr Mousavi's perseverance.

The author is a professor of Sociology at Eastern Michigan University and has conducted numerous opinion surveys in the Middle East.

© Project Syndicate, 2009 www.project-syndicate.org