More than 50 million Iranians are invited to vote today in elections that Ali Khamenei, the Supreme Guide of the Islamic Republic, has described as “fixing the frontiers” with the American Great Satan.

At stake are 290 seats in the Majlis, the make-believe Parliament set up by the mullahs after they seized power in 1979. Although relations with the United States, or rather lack of them, are not an issue for the 3,000 “approved” candidates, Khamenei is right in presenting the election as an indirect referendum on President Ahmadinejad's dangerous foreign policy. The issue is whether the mullahs will lose yet more control to the Islamic Revolutionary Guards (IRGC) and, if so, which faction of the guards will emerge triumphant, the radicals or the realists.

The IRGC is a parallel army of more than 250,000 men, created by the Ayatollah Khomeini as his regime's praetorian guard. Over the decades, however, it has emerged as the backbone of the ruling Establishment - especially, since it controls more than 500 companies with interests in everything from oil to tourism. Thanks to a network of retired officers and veterans, the IRGC has a presence throughout the state, as well as large chunks of the private business sector. Since the mid-1990s, the IRGC has been trying to expand its political power base, mostly at the expense of the mullahs and their business associates.

A win by the most radical faction, which is close to President Ahmadinejad, would postpone any rapprochement with the US, as well as any hopes of liberalisation at home, for at least another four years. But a win by the more pragmatic faction, former and active IRGC officers who have amassed great personal wealth, could herald an easing of tension with the West and, perhaps, less repressive methods at home.

From the way this election is being organised it is clear that the mullahs, who have constituted the largest single bloc in all previous parliaments formed under the Islamic Republic, are on the way to losing a good part of their political clout. Having captured the presidency from the mullahs in 2005, with the victory of Mahmoud Ahmadinejad, the IRGC is now determined to consolidate its position by securing a majority in the Majlis.

To make sure that things go according to script, the IRGC has seized full control of the entire electoral process, treating it as a military operation led by one of its commanders acting as Deputy Interior Minister.

Elections in Iran are held under exclusive government control - there is no independent oversight, no foreign observers and political parties are banned. To limit the choice, candidates are vetted by the security services and the IRGC. The list of approved candidates is drawn up by the Council of the Custodians of the Constitution, while the Supreme Guide can include or exclude anyone from it. Campaigning is limited to two weeks, not enough for most candidates to achieve even name-recognition.

Many prominent Iranians, among them people who had worked for the Khomeinist regime for years, have called for a boycott of the polls. Many others way wonder what is the point of the exercise. But holding elections, even under these peculiar circumstances, is a perverse way of acknowledging the people as the ultimate source of power, a kind of tribute that vice pays to virtue. The elections to the Majlis, however circumscribed, give a sense of the shift of power within Iran and enable the ruling Establishment to sort out its internal rivalries without bloodshed.

Today's election is the eighth since the mullahs seized power in 1979. In the first two, the mullahs purged the Marxist-Islamist and communist elements. Then, in the following election, it was the turn of self-styled religious nationalists to be purged. The fourth to sixth elections helped to alternate power between two wings of the same group of Khomeinist mullahs who had carried out the purges. And the seventh marked the large-scale entry of elements from the IRGC into the Majlis.

The current election is like a primary within the IRGC: rival factions are fighting over a bigger share of power, while the mullahs play second fiddle. In most of the previous elections, the choice was between turbaned heads; in today's exercise, the choice is between military caps.

If all goes according to script, a coalition of three blocs led by retired IRGC officers will win the largest number of seats with the blessing of the Supreme Guide, who is reportedly unhappy about President Ahmadinejad's attempts at building an independent popular base for himself.

With a Majlis hostile to the provocative President, the Supreme Guide would have a better chance of clipping his wings without forcing a direct confrontation. But the price that Khamenei may have to pay is a further extension of the IRGC's power and a corresponding retreat by the mullahs.

Representing the most radical wing of the Establishment, President Ahmadinejad is sincere in his belief that he could drive the US out of the Middle East and give the Khomeinist revolution a new momentum towards its goal of global victory. His adversaries are mostly men who, having made immense fortunes, are more interested in preserving the system than risking its survival with a strategy of permanent revolution. They reject President Ahmadinejad's dangerous illusions about global conquest with the help of the Hidden Imam and don't believe that Iran should be kept at the edge of war through its confrontation with the United Nations over the nuclear issue.

Whatever the outcome of the election, the result will not bring Iran back into the mainstream of global politics. Regardless of who controls the Majlis, the Islamic Republic is likely to remain a threat to its neighbours and beyond for some time yet. A victory for the IRGC's moneybags, however, could help to revive the old debate about “revolution in one country” versus “permanent revolution”. President Ahmadinejad regards revolution as similar to riding a bicycle, you keep going as long as you pedal. His realist opponents within the IRGC favour the “revolution in one country” option and argue that a less aggressive foreign policy could help to end the Islamic Republic's isolation and remove the threat of war.

Mahmoud Ahmadinejad - who has described the Khomeinist regime approvingly as a train steaming ahead without brakes - behaves as if he has nothing to lose. The election may bring him face to face with men who do have something to lose and are anxious to avoid loss.

Amir Taheri was executive editor-in-chief of Kayhan, Iran's largest newspaper, 1972-79

Times Recommends

• Never believe Demjanjuk is a ‘victim’
• A strong City is not just good for Britain
• Class warrior ready for one last battle