By Roger Hardy
BBC Middle East analyst
By recently renewing a six-month ceasefire, the young Iraqi Shia cleric Moqtada Sadr has won praise from the United States and from the Baghdad government.
Moqtada Sadr hopes to do well in October elections
But will his new-found moderation last?
Mr Sadr has long kept people guessing.
In the early days after the US invasion of Iraq in 2003, he was often dismissed as a naive young firebrand.
President George W Bush once described his militia, the Mehdi Army, as a "band of thugs".
But Patrick Cockburn of the Independent newspaper, author of a forthcoming book about the cleric, thinks the Americans have consistently underestimated him.
Mr Cockburn regards him as the leader of the only genuine mass movement in Iraq - made up of tens of thousands of impoverished young Shia in southern Iraq and in the sprawling Baghdad suburb of Sadr City.
He also believes the young cleric learns from his mistakes.
Twice in 2004 the Sadrist movement rose up in revolt against the American presence in Iraq.
The two revolts burnished his reputation as a fierce opponent of foreign occupation - but militarily his men were no match for the Americans.
"Now," says Mr Cockburn, "he doesn't enter a confrontation unless he's sure he can win it."
In 2005, he began to turn his struggle into an essentially political one, competing in elections and winning a significant bloc of seats in parliament.
But he refused to disband the Mehdi Army, which remained a force to be reckoned with.
And the following year, as Sunni-Shia violence intensified, the militia was increasingly accused of brutal sectarian killings and criminality.
Nadje al-Ali of London University, author of a recent book about Iraqi women, says the movement's record is distinctly mixed.
"It's a source of survival for many people in a situation where there's no functioning state."
But, she adds, the movement has put pressure on women to cover up and stands accused of involvement in a string of so-called "honour killings" - particularly in the southern city of Basra.
More than 100 women were killed in Basra last year alone.
In some cases their bodies were found in rubbish bins.
Senior Sadrist official Baha al-Araji denies that Sadrists were involved.
"The acts you are referring to run contrary to the Islamic approach," he told the BBC, "and so they are not acts we would carry out."
He implied that neighbouring states have a secret agenda to destabilise Basra because of the city's importance as a source of much of Iraq's oil wealth.
Sadrists have been accused of forcing women to wear Islamic dress
He also denies that Sadrists force women to follow an Islamic dress code.
Last year, Moqtada Sadr ordered the Mehdi Army to observe a six-month ceasefire - a ceasefire he recently renewed.
Mr Cockburn believes he did so in order to avoid confrontation with the Americans and to get a tighter grip on his famously ill-disciplined militia.
Baha al-Araji admits that local gunmen and criminals have discredited the Mehdi Army by acting in its name - and says that, during the ceasefire, more than 700 people have been expelled from the movement.
So where do the Sadrists go from here?
Provincial elections, due to be held in October, will provide an important test of the movement's support.
Observers believe it is poised to do well against its main Shia rival, the Iranian-backed Islamic Supreme Council of Iraq led by Abdel-Aziz al-Hakim.
Political squabbling has cast some doubt on whether the October deadline will be met.
But if the elections go ahead and the Sadrists sweep the south, this would give them a significant say in determining the future of Iraq.