Could Iraq's democratic future depend on an old man lying in a London hospital bed?

It's no coincidence that the ceasefire in Najaf has broken down while Sistani has been incapacitated

While the world is watching Najaf bleed and burn, the future of Iraq will pivot on what happens in a private hospital bed 3,200 miles away. The story of a frail 74-year-old man undergoing a triple heart bypass operation in London might seem a sideshow while US troops and Muqtada Sadr's Mehdi Army are turning an Iraqi city into a live arms dump. But that old man is Ali al-Sistani, a grand ayatollah - and he is Iraq's best hope for democracy.

While the world is watching Najaf bleed and burn, the future of Iraq will pivot on what happens in a private hospital bed 3,200 miles away. The story of a frail 74-year-old man undergoing a triple heart bypass operation in London might seem a sideshow while US troops and Muqtada Sadr's Mehdi Army are turning an Iraqi city into a live arms dump. But that old man is Ali al-Sistani, a grand ayatollah - and he is Iraq's best hope for democracy.

A democratic ayatollah? At first, the idea sounds preposterous, like a black Ku Klux Klansman, a Jewish Nazi or an intellectual member of the Bush family. The Ayatollah Khomeini is still the West's mental template, a tyrannical theocrat who slaughtered more than a million Iranians and issued a fatwa against Salman Rushdie.

But democratic instincts spring up in the strangest of places. Many Shias insisted that Khomeini was an anomaly, a radical departure from the millennium-old Shia tradition of "quietist" clerics who did not seek personal political power. I was always pretty sceptical, and I'm instinctively hostile to religious authorities - but the behaviour of Sistani since the fall of Saddam has proved them right. From his home in Najaf, Sistani has been an absolutely consistent campaigner for a free and democratic Iraq, while scrupulously avoiding any temptation to seek power for himself.

Still sceptical? I know I was. True, Sistani had a reputation for speaking out for Shia rights during Saddam's tyranny, bravely inserting coded warnings to the dictator into his sermons. But when Saddam's dictatorship was finally destroyed and Sistani began to call for democracy, I assumed this was simply a cynical ploy. Surely an ayatollah could only want one man, one vote, for five minutes? Wasn't Sistani hoping for the election of a theocratic government that would quickly find excuses to liquidate a free press and hold rigged semi-elections thereafter?

But then Sistani pulled off a democratic triple whammy. He reached out to Iraq's Sunnis and Christians, and called on the Shia to protect them from both the Coalition and from al-Qa'ida attacks. He told the Americans they could not hand-pick delegates to Iraq's constitutional assembly; they must be chosen by "a full and free vote". And then his many religious texts began to be translated into English - and it became clear that in the civil war within the Muslim world, Sistani is clearly in the moderate, democratic camp.

Read his book A Code of Practice For Muslims in the West. It is - in Muslim terms - a startlingly progressive text. Sistani stresses the importance of respecting democracy, arguing that Muslims should participate in electoral politics - as voters and candidates - on an equal basis with non-Muslims. This might sound like a platitude, but compare it with the message preached across the Arab world by Islamofascist groups like al-Muhajaroun, who argue, "Muslims must not vote for anyone in elections... It is idol-worship. There is no legislator but Allah, and the only law should be Sharia".

Before the war, some of us argued that, in a Saddam-free Iraq, democratic strains of Islamic thought would begin to emerge. We were right - but the violence has been so terrible that nobody noticed. Reuel Marc Gerecht, an expert in Shia political thought, says that Sistani's philosophical arguments for democracy are "almost unprecedented in their scope. He speaks the language of inalienable rights: one man, one vote, and a constitution written by elected representatives and approved by popular referendum. Sistani has managed to launch a project that Muslim progressives have only ever dreamed of: establishing a democratic political order sanctioned and even protected by the clergy." Here are the slow, tentative roots of the Islamic Reformation so badly needed in the Middle East.

Islamic fundamentalism will not ultimately be defeated by a crusading West. No; moderate Muslims are the key - and Sistani is probably the most influential moderate Muslim alive today.

Of course, he has views on social issues that, to a Western leftie, are (at best) distasteful. He is critical of divorce and he certainly isn't going to be joining any Gay Pride parades. But he believes in opening up a democratic space in which these ideas can be discussed, and he believes in abiding by the decision of the majority. This is a massive advance.

Still some people suspect Sistani is a closet theocrat whose democratic arguments will quickly melt when he is close to power. Why then has he repeatedly and blatantly rejected the Iranian political model, where Mullahs "oversee" (read: censor and control) the democratic parliament and press? He could have single-handedly placed the Mullahs at the heart of the debate about Iraq's constitution; instead he has insisted they remain outside state structures, in the democratic forum.

There were many honourable critics of the war on the left, and some of their arguments have been vindicated. But there was a conservative critique of the war - based on the belief that Iraqis would seek another dictator as soon as Saddam was gone - that has been proved totally wrong. For example, Simon Jenkins, the former editor of the Times, declared that "only a fool" could believe Iraqis were capable of democracy. "Democracy will merely serve as a transition to Shia theocracy, Iran-style, while Sunnis and Kurds break loose." The incredible popularity of Sistani's arguments for democracy - and the massive explosion in membership of democratic trade unions across Iraq - shows how pernicious this view is.

It is no coincidence that the cease-fire between the Coalition and the Mehdi Army has broken down while Sistani has been incapacitated. He has proved to be a crucial restraining force on both Sadr and the Coalition. He tried to direct the Mehdi Army's (often legitimate) anger about unemployment and human rights abuses away from violent protest and towards democratic organisation. He could have played an important role in restraining the increasingly disturbing behaviour of Prime Minister Iyad Allawi, who has just reintroduced the death penalty and banned al-Jazeera - the most vigorous example of a free media in the region - from Iraq for a month.

The only response to this increasing authoritarianism and rage is to make a clear case for Sistani-style moderate democracy. It's always tempting to reduce politics to force, to guns, to raw power. As we see terrible footage of fighting from Najaf over the next few days, the temptation will be almost unbearable. But politics is ultimately about ideas. Even so psychopathic a wielder of power as Joseph Stalin once admitted "ideas are more powerful than guns".

The idea of democracy is breathing and kicking and fighting in Iraq, and it needs to be defended against anyone - from Muqtada Sadr to George Bush - who might find it inconvenient.

Supporters of freedom in Iraq like me now find themselves in the strange position of desperately hoping for an ayatollah to survive. If he dies before his political philosophy has won Iraq's battle of ideas, his arguments should outlive him. But I fear they may be drowned out by the sound of gunfire.

j.hari@independent.co.uk