Ayad Allawi's ultimatum yesterday to the rebel Shia cleric Moqtada al-Sadr who is holed up with his fighters in the holy city of Najaf was notable for one thing: the lack of a deadline. Reporters who gathered for a news conference in Baghdad were expecting the prime minister to announce that the final military push to remove Mr Sadr from the Imam Ali shrine had begun. But while he made it clear that the time for negotiation was over, Mr Allawi positioned himself behind the peace plan that emerged from this week's national conference, which calls for Mr Sadr to vacate the holy shrine, disarm his militia and join the political process. "A solution is needed and soon and we want to use all peaceful means to preserve the holy shrine," he said.
It was an indication that the prime minister, who has been cultivating his image as a no-nonsense leader, is aware of the risks involved if he or the US forces make a false move in Najaf. If the plan to neutralise Mr Sadr works, Mr Allawi will then have only the insurgency in Sunni areas to worry about. If it fails, his government's aim of restoring security so that elections can be held will be little more than wishful thinking.
For while there is little doubt that a US and Iraqi military campaign could dislodge Mr Sadr's dedicated but poorly trained al-Mahdi fighters, the political fallout could inflame mainstream Shia opinion, which broadly disapproves of Mr Sadr and which Mr Allawi desperately needs on his side. In the course of either arresting or killing Mr Sadr and his young armed followers, US and Iraqi forces run the risk of being seen as "desecrators" of sacred Najaf, an act that could linger in the minds of any disaffected Shia the majority in Iraq.
"Anything affecting the holy shrine may result in disaster," said Adel al-Adib, a senior official of the Dawa party, a major Shia group which is part of the interim government. "The reaction will last for a long time." The short-term consequences could be destabilising, too. "It could be portrayed as the first real atrocity of the new interim government," Mr Adib said. "Sadrists have already started likening Mr Allawi to Saddam. If the military way is the only one pursued, it could fail and the government could lose credibility, and where would that leave us on the next step to complete sovereignty? The danger is the government will indeed be seen to be doing things like the former regime."
Mr Sadr, who is in his early 30s, benefits from the popularity of his father, a Shia cleric killed by Saddam Hussein's regime in 1999.
He knows he cannot rival the Shia Ayatollah Ali al-Sistani in terms of religious standing, but is vying to become the paramount Shia political power. And while Mr Sistani remains away from Najaf he has just left hospital in London after heart surgery there is a danger that Mr Sadr's control of Najaf will solidify.
Whatever Mr Allawi thinks of Mr Sadr he is variously described as unstable or stupid by government officials he has tapped a vein of Iraqi and Arab nationalism, particularly among the poor, alienated Shia youth.
The unrest has prompted a number of senior Shia figures in the south to call for secession from Baghdad.
Some foreign diplomats question whether the destruction of Mr Sadr would really have a beneficial effect.
"Destroying the Mahdi army may fragment a group of youths who at least for now are under some sort of control," one said. "If you remove their leadership, then the Shia resistance may get into a macho contest with the Sunni resistance over who can outbomb the other."
But many agree that the costs of inaction are equally heavy. The number one on most Iraqis' wish list is security, followed by jobs, services and a chance to have a say in their own future.
Until now Mr Allawi's unelected administration has bought some breathing space by promising a secure environment that allows the reconstruction of the country and fair elections.
"If the interim government cannot meet its first major challenge, then its credibility will lie in tatters," said a western diplomat.
"This is a chance for the new Iraqi state to establish the primacy of the state and the rule of law. National elections with an armed militia on the loose is unthinkable."
Mr Allawi has gone out his way to open the door to Mr Sadr."If the Iraqi people want Mr Sadr to be their leader, they will be able to elect him," he said again yesterday.
Mr Sadr refuses to recognise the interim government. But his decision this week to agree to the terms of the national conference, plus the presence of his supporters there, indicate some willingness to deal with new institutions in Iraq.