The election as president of Iran of Ebrahim Raisi, a hardline judiciary chief and protégé of Ayatollah Ali Khamenei, the supreme leader of the Islamic republic, has tipped the balance of power decisively towards the theocrats and their praetorians, from the judiciary to the Revolutionary Guard.

Yet it was always the case that Islamic institutions, mostly appointed and answerable to the supreme leader, outweighed the democratically elected, republican institutions accountable to the voters, such as the presidency and parliament.

What has changed, however, is that a clear majority of Iranians has abandoned electoral politics. Major elections in the Islamic republic have hardly been free and fair but now the valve on Iran’s sociopolitical pressure cooker has melted.

The turnout of 48.8 per cent this month was the lowest in the Islamic republic’s history of contested presidential elections. The outgoing president, Hassan Rouhani, was re-elected with 24m votes in 2017; Raisi got 18m. But not only did more than half of Iranians spurn the poll, 3.7m who did vote spoiled their ballots — more than voted for either of Raisi’s feeble rivals, after theocrats banned viable candidates.

A majority of Iranians clearly has no time for Raisi. The aspirations of the country’s young population to rejoin the world, evident in Rouhani’s two victories, have no place in elections where the result is preordained by Khamenei and the clerics. This majority, moreover, has come to see reformist and hardline camps as differing mainly on how best to preserve the system. Neither faction questions the right of theocrats to over-rule democrats.

This is not just an outlandish survival of the theory of divine right into the 21st century. Most Shia Muslims worldwide, including many in Iran’s higher clergy, regard the core premise of the theocrats — “the guardianship of the jurisprudent” (Velayat-e Faqih) of Ayatollah Ruhollah Khomeini, the first supreme leader — as doctrinally spurious and dragging their religion through the mire of factionalism.

Many ordinary Iranians seem simply fed up with ageing reactionaries using an already fossilised ideology to protect their power and privileges.

Obviously, this did not happen overnight. The regime has systematically purged inconvenient politicians appearing as tribunes of the people. Reformists such as President Mohammad Khatami (1997-2005), pragmatists such as outgoing President Rouhani, or even mainstream conservatives such as Ali Larijani, the former speaker of parliament banned from standing in this month’s presidential election, have all been sidelined by the lords of Iran’s labyrinthine politics.

These figures mostly emphasised civil rights, combating corruption and upholding the rule of law — random and negotiable currencies in this clerical mafia. Mir-Hossein Moussavi, veteran revolutionary and former foreign and prime minister in the 1980s whose presidential bid was suppressed and his Green Movement put down without mercy in 2009, remains under house arrest.

But Iranians are no strangers to insurrection, going back to the 1979 revolution against the monarchy of the Shah that stunned the world. A bit like the old Irish rebel boast of a “rising in every generation” Iranians have staged a civic uprising roughly every decade.

In 1999, students took to the streets to press Khatami on his reform promises. In 2009, the Green Movement protested against what it said was a rigged election. Both were mainly Tehran phenomena. In the autumn of 2019, however, protests spread across urban Iran and embraced organised workers, and were violently suppressed.

The reason there was no uprising in the 1980s was the regime acted to forestall one. With paranoia about fifth columnists growing at the end of the 1980-88 war with Iraq, Tehran executed thousands of political prisoners, including leftists, a bloodbath in which incoming President Raisi is alleged to be responsible. Raisi, as head of the judiciary, a bastion of the theocrats, is under US sanctions for that and repression in 2009.

While the theocrats unquestionably dominate the bastions of power, they have to start orchestrating the succession to Khamenei, 82, as supreme leader, a post for which Raisi is seen as frontrunner. The problem is he (and they) lack popular legitimacy among a population prone to express itself.

The regime seems conscious it has to offer its young citizens a horizon of greater opportunity and the social freedoms they are seizing without permission from the clerics. That might put a makeshift valve back on the pressure cooker. But the problem is structural.

The late former president Akbar Hashemi Rafsanjani, the great pragmatist of the revolution and arch-fixer at the heart of Iranian realpolitik for more than three decades, floated the idea of a leadership council to eventually replace the supreme leader when the time comes. This was after he triumphed in 2016 elections in Tehran to the Assembly of Experts, the arcane but elected body charged with selecting the leader.

That already seems an age ago, but uprisings can come more than once a decade.