This opinion article is by Adjunct Professor Amin Saikal from The University of Western Australia's School of Social Sciences.
The outcome of Iran's weekend election has propelled the reformist faction to the top political office.
While historic and a sign of growing dissatisfaction within Iran, challenges confronting the new president cannot be overestimated.
Masoud Pezeshkian, who beat his ultra-conservative opponent Saeed Jalili, has promised to put Iran on a course of reform and moderation on the domestic and foreign policy fronts.
As an experienced former legislator and health minister, Pezeshkian has a public mandate to initiate substantial changes.
He needs to improve his country's faltering social and economic landscape, and foreign relations with the West, and thus arrest the waning power base of the Islamic regime.
Many Iranians have grown deeply disillusioned with the regime's theocratic impositions, including compulsory hijab wearing for girls and women, economic mismanagement and an inability to rein in endemic corruption.
They have equally shunned the regime's costly maintenance of regional proxy forces - the Iraqi militias, Syrian regime, Lebanese Hezbollah and Yemeni Houthis - against their arch-enemies, Israel and the US.
There have been growing calls for an end to the regime's system of Shiite rule of the "Islamic Jurist" under a powerful supreme leader - a position Ayatollah Ali Khamenei has held since 1989, following the death of the regime's founder, Ayatollah Ruhollah Khomeini.
The victory for Pezeshkian is not the first time a centrist reformist has come to power.
His predecessors, Mohammad Khatami and Hassan Rouhani, were also like-minded, seeking to address discontent and improve foreign relations.
But their achievements were limited and frustrated by conservatives, including Jalili.
Khatami stood for a "dialogue of civilisation" in foreign policy. Rouhani negotiated the 2015 Iran nuclear agreement with world powers, including the US, which limited Iran's uranium enrichment to 3.67 per cent.
But the deal was wrecked in 2018 by President Donald Trump, who withdrew from the agreement and accused Iran of being a regional threat. Since then, Iran has accelerated its uranium enrichment to a threshold level.
Whenever the chips have been dangerously down, the supreme leader and conservative factions have expediently allowed the reformists to rise to the occasion and smooth out some of the rough edges of the regime's behaviour.
But only to the extent not to undermine their dominance.
Khamenei knows that the state-society dichotomy has widened, and that Iran is amid a regional situation whereby it potentially faces a war with Israel and the US over its support of Hamas, the Palestinian cause, and its "axis of resistance".
Beyond this, the Islamic regime faces a change in supreme leader sooner rather than later. Khamenei is 85, with no apparent successor. President Ebrahim Raisi, who died in May, and Khamenei's son, Mujtaba, were touted as possible successors.
Although Mujtaba remains in the race, it is now in Khamenei's interest to leave behind a factional balance and more stable Islamic system for the choice of a successor that would ultimately be determined by the constitutional body of the Council of Experts, whose task is to appoint and dismiss a supreme leader.
As a result, the new president will have an opportunity to press on with some of his economic, social and foreign policy reforms to promote a more humane face of the Islamic regime.
But his moves will be watched closely not only by a sceptical West, but more importantly by his internal opponents, who will want to make sure he does not engage in any structural changes to undermine their dominance in the system.
Pezeshkian has his work cut out.
Amin Saikal is an Emeritus Professor at the ANU and Adjunct Professor at The University of Western Australia, and author of Iran Rising: The Survival and Future of the Islamic Republic.