It was only after an Iranian-born cleric, who almost never leaves his home in Najaf, called on Iraq’s prime minister to quit did he respond to street protests and resign.
The prime minister’s removal in November was not the first time the political direction in Iraq had been guided by the reclusive Grand Ayatollah Ali Al Sistani.
The protests, in which the authorities and militia supported by Iran killed hundreds of civilians, highlighted a transformation in Mr Al Sistani’s approach to politics.
His influence has become more open in response to challenges from a relatively upstart cleric and a need to accommodate Iran’s hardline clerical rulers.
As most of Iraq’s Shiite elite coalesce to intensify a crackdown supported by Iran, Mr Al Sistani’s authority may have never been more in demand, and never more in danger of being swept away.
In his late eighties, Mr Al Sistani is the main religious authority, or marjaa -- reference -- among Iraq’s majority Shiites, having moved to Najaf from Iran in the 1950s.
He succeeded Grand Ayatollah Mohammad Abu Al Qassim Al Khoei as the most powerful figure in Najaf's Hawza, as the senior Shiite clerical leadership is known, in 1992.
As such he oversees a large chunk of the sect’s religious finances, mostly sourced from alms by Shiites around the world.
Mr Al Sistani pays for the salaries of thousands of seminary students and clerics who follow him in Iraq and abroad.
Almost every player in Iraq since 2003 has had to take him into account. Among them is the US, whose officials were granted a meeting with Mr Al Sistani as Saddam Hussein was being toppled in March 2003.
After the Iraqi uprising broke out in October 2019, the government and militia supported by Iran turned their guns against the mostly Shiite protesters.
Many are rebelling against a system that Mr Al Sistani was instrumental in bringing about.
He had insisted that the US speed up the timing of Iraq’s first elections after Saddam was toppled, and opposed Washington’s plans to have an unelected body draft a constitution.
In the first elections, in January 2005, Mr Al Sistani backed a Shiite political alliance, instructing the Hawza staff to campaign on the list’s behalf.
Many of the alliance’s members and their associates comprise the core of today’s political class – the very group the protest movement wants removed.
Since 2003, he has faced competition from populist cleric Moqtada Al Sadr who, despite his ties with Iran, is regarded as more of a nationalist figure.
Mr Al Sistani speaks Arabic with a Persian accent, according to politicians who have met him, although he is not close to any of Iran’s clerical rulers nor meets them publicly, as Mr Al Sadr does.
Mr Al Sadr burst on to Iraq’s religious and political scene as Saddam was being toppled.
A mob loyal to Mr Al Sadr killed Abdulmajid Ali Al Khoei, the son of Mr Al Sistani's predecessor, on April 10, 2003, a day after US-led invasion ousted the dictator.
The murder, which became known as "the massacre at the shrine", claimed the lives of several other people loyal to Al Khoei and shaped Mr Al Sistani’s ties with Mr Al Sadr.
Ali Al Khoei was stabbed on the grounds of the Imam Ali Shrine in Najaf, site of the grave of the second most revered figure in Shiism. His body was attached to a car and dragged through Najaf's streets.
The US-backed Al Khoei and Mr Al Sistani shared a belief in non-violence, meeting only days before the massacre.
It ensured a permanent lack of trust between the two men, and the killing of an ally forced Mr Al Sistani to go into hiding, until Mr Al Sadr’s power was checked by rival Iraqi Shiite militia that poured in from Iran, and by US forces. Both were wary of Mr Al Sadr’s influence expanding.
The Iraqi judiciary issued an arrest warrant for Mr Al Sadr a few months later. But it was not enforced, partly because he mounted at least two uprisings against US forces that deflected from the murder, and because of his Iranian backing.
In 2011, Iraq’s Higher Judicial Council, which adjudicates on contentious legal matters, said there was no evidence to justify bringing Mr Al Sadr in for interrogation over the Al Khoei murder.
Mr Al Sadr’s rise contributed to Mr Al Sistani abandoning the quiet approach to politics that helped him to survive Saddam.
In 2004, Mr Al Sistani was lauded by his supporters, and by some of his critics, as the saviour who ended bloodshed when he negotiated a truce after US forces surrounded Mr Al Sadr in the Imam Ali Shrine.
The saga of the downfall of prime minister Adel Abdul Mahdi, and Mr Al Sistani’s role in it, indicates his stature has grown to where he has become the final arbiter of Iraqi politics.
But he shares this position with Iran, which has an expansive client network in Iraq and whose rulers follow Khomeinism, an ideology at odds with Mr Al Sistani’s mostly non-violent creed.
Tehran has a complex relationship with Mr Al Sadr, backing him but supporting other players at the same time to curb his perceived unreliability as an Iranian ally.
Mr Al Sistani is a figure too established to play an Iranian stooge. He is opposed to Ruhollah Khomeini’s theory of Vilayat-e Faqih --rule by the jurist -- which forms the basis for the political power of the clergy in Iran.
Although Mr Al Sistani has long managed his relations with Tehran, if his differences with the country’s leadership do come to a head he lacks the militia strength Iran has in Iraq.
Many of the militias were formed or strengthened in 2014, when Mr Al Sistani issued a fatwa calling on Iraq’s Shiites to take up arms against Sunni extremists.
He ignored warnings by centrist Sunni figures that such an edict would create "mob rule" and lead to reprisals against Sunni civilians, many of whom were later killed by militia death squads.
Earlier in December, Mr Al Sistani called for early elections to be held after a “fair” election law was passed.
The announcement, like many by Mr Al Sistani, lacked specifics and was issued through a representative who delivers the Friday sermon on his behalf.
Mountings killings of civilians drove other clerics to be more detailed in their vision for a solution.
Mr Al Sistani may have lost much of his sway over the militias he helped to unleash with the fatwa. Many Iraqis had looked to Mr Al Sistani after his intervention in 2004 to help the country shed decades of violence and become a real democracy.
His approach to politics had grown less subtle, but it contributed to keeping Iraq united after the US invasion and defeat of Sunni militants.
With time running out, he has not found an answer to Shiite extremists.
Mr Al Sistani is rooted in the Najaf seminaries and their political and religious intrigue, an anachronistic world many in the protest movement sweeping Iraq may find unfathomable or do not want to understand.
He remains a figure above criticism but he needs to find contemporary, and clear, way to address the millions of young Iraqis on the streets or his role will be eroded.