In the summer of 2014, the Islamic State cemented its hold over much of Iraq, and unleashed a torrent of atrocities. The spectacle of 1,700 Iraqi army cadets summarily executed at Camp Speicher on the banks of the Tigris sent shockwaves of grief and fear through the nation.

As state institutions buckled and the army of extremists, including foreigners, closed in on Baghdad, a figure revered in Iraq but unknown to much of the world called for volunteers to take up arms and begin to turn the tide against the Islamic State. Shia cleric Grand Ayatollah Ali al-Sistani, at the time an ascetic eighty-five-year-old, delivered his decree through a Friday prayer sermon read by a representative on June 13, 2014: “Citizens who are able to bear arms and fight terrorists in defense of their country, people, and sanctities,” he said, “must volunteer to join the security forces.”

That fatwa is but one of the starkest examples of Sistani’s decisive influence, not just in Iraq but in the wider world of Shia Islam. Sistani has done more to stabilize Iraq than any other figure, and has appealed to a majority of the world’s tens of millions of Shia Muslims with his indirect model of clerical authority—a stark contrast to the competing model of direct clerical rule advanced by his compatriots in Iran.

This is the crux of the analysis of God’s Man in Iraq: The Life and Leadership of Grand Ayatollah Ali al-Sistani, my new Century International book. In the book, I draw on new sources and hundreds of interviews during decades of fieldwork inside Iraq to argue that Sistani has redefined the role of the Shia clergy in politics.

Quiet Influence

The message of Sistani’s June 2014 decree was simple enough: Iraqis of all faiths had an obligation to unite and rise up against the Islamic State. However, for a country emerging from conflicts across several decades, including a grinding civil war fought along sectarian fault lines, this was no small ask. Remarkably, Sistani’s decree worked. Fighters from all backgrounds flocked to the Iraqi security forces and to allied militias; most were Shia, some were also Sunni, Christian, and from other minority communities in Iraq. And they successfully repelled the Islamic State. Known today as the jihad fatwa, Sistani’s decree marked a turning point in the history of Iraq after the fall of Saddam Hussein.

Sistani was able to unite the country in the face of the Islamic State because of the tremendous influence and respect he commanded in the Shia community both in Iraq and beyond. His character and philosophy account for a great deal of this respect. In a landscape of fiery preachers and corrupt politicians, Sistani stands out for his circumspect and practical views. He believes that clerics cannot dictate government but must, instead, serve the people—in contrast to the clerics who rule Iran, who claim that religious leaders must lead the government. He is reluctant to intervene in politics, and quick to call for patience among the faithful.

Sistani has appealed to the world’s millions of Shia Muslims with his indirect model of clerical authority—a stark contrast to the competing model of direct clerical rule in Iran.

Sistani’s network of clerics and foundations in Najaf, one of the holy cities of Shia Islam, also bolsters his influence and authority. Formed through years of alliance-making and internal deliberations among elite scholars, these networks are specific to the hawza—the Islamic seminary in Najaf, an ancient institution of knowledge and customs historically shielded from the outside world. Senior clerics choose whom to follow based on factors like an ayatollah’s learnedness, academic lineage, and demonstration of wisdom. Sistani’s network is exceptionally strong, and he is known not just as a marja (guide), but as the supreme marja of Shia Islam: a first among equals. He is arguably the most influential Shia cleric since the early Safavid era (1501–1629 C.E.) because of his success in consolidating authority in multiple spheres at once: religion, politics, and international recognition.

The Voice of Reason

Sistani’s jihad fatwa is only one of numerous achievements in a lengthy career. Born in Iran, he distinguished himself as a brilliant student in the seminary of Najaf when he moved there in 1951. Later, he survived the repression of Saddam’s regime and emerged as a reluctant marja in 1992 following the death of his mentor, Ayatollah Abu al-Qasim Khoei. After 2003, Sistani became a determined voice for democracy in the face of the American occupation. He embraced Iraqi self-determination and called for elections as soon as possible. He played a pivotal role in calming several volatile situations during the occupation without ever kowtowing to the United States, from the pitched 2004 Battle of Najaf to the bloody sectarian strife that gripped Iraq from 2006 to 2008. He has publicly opposed corrupt Shia politicians who seek his favor. Through it all, he has maintained a famously spartan lifestyle and has never been known to stray from his principles.

A leader of this stature in practically any other religion would probably be a household name around the world—a figure on par with the Pope. Yet Sistani is not so well-known outside of Shia Islam and the Middle East. God’s Man in Iraq: The Life and Leadership of Grand Ayatollah Ali al-Sistani (The Century Foundation, December 2023) is an attempt to remedy this critical gap in knowledge of Iraqi and Middle Eastern affairs. The book contains dozens of passages from never-before-translated sermons, and explains Sistani’s unique power within the traditional apparatuses of Shia Islam. It tracks Sistani’s political life and his accomplishments—as well as providing objective analysis of his interventions and role as a major figure in modern Iraq.

Like any leader, Sistani is not without his detractors and critics. The biggest complaint is that his jihad fatwa gave rise to the fractious Popular Mobilization Units (the PMU), paramilitary organizations that have become mired in corruption since they helped defeat the Islamic State. And later, as the youth-driven Tishreen movement sought to overturn the corrupt status quo in Iraq, the aging Sistani had mostly withdrawn from politics—though he did so, like the youth in the streets, in protest of the government.

Overall, however, the cleric, now ninety-three, stands out for cutting a figure of singular integrity and ethics through decades of turmoil, regime change, and nearly apocalyptic challenges. Sistani has been the most consistent actor in Iraq pushing for stability, progress, and self-determination. He will be remembered as a voice of reason in an age of violence, fear, and uncertainty.

Header image: An Iraqi man holds a picture of Grand Ayatollah Ali al-Sistani during a demonstration welcoming Ibrahim al-Jaafari, then the Iraqi prime minister, to the holy Shia city of Najaf on December 17, 2005. Source: Saad Serhan/Getty Images