For the American authorities, Sadr was a rabble-rouser and a barrier to peace, a hostile religious figure whose influence was significant and malign.
But times change, and now Sadr is cutting a more conciliatory figure. He may even be an essential participant in mainstream politics; undergoing a process of moderation himself.
Notably, his militia, now revived and renamed Saraya al-Salam, is participating in the fight against the Islamic State (IS). This conflict has put many disparate factions and forces within Iraq on the same side, for IS has given them a common enemy. This anti-IS campaign has the potential to become a war of Iraqi national unification.
Sadr's place in all this could be difficult to pin down. But recent developments suggest that he is undergoing something approaching a process of moderation.
Gareth Browne, a journalist currently covering the Mosul campaign, wrote an important piece in February this year suggesting the same.
I contacted Browne to ask whether more recent events confirm his thesis. He said that there is a sense that "some Sunni leaders recognise [Sadr] isn't going anywhere, and are willing to consider his olive branch". Browne added that "there is talk of launching a cross-sectarian party in time for next year", though this is "just talk at the moment".
Sadr's sympathies are nationalist, meaning that he rejects much regional Shia chauvinism, which is associated with Iran, and takes a more specifically Iraqi tack. He is therefore a strong critic of Nouri al-Maliki, formerly Iraq's prime minister, who is seen by many as Iran's man in Baghdad.
As ever, the fate of more than one nation is involved. Iranian intervention in Syria, which nakedly promotes regional sectarian interests, complicates matters. And opinions are frequently divided along sectional interest rather than secular political lines.
An important part of Sadr's apparent moderation is his stance on Syria. Recently, Sadr called upon Bashar al-Assad, Syria's dictator, to resign. This was, tweeted Middle East analyst Nibras Kazimi, a "first for organised Shiism".
Sadr went against the grain among Shia figures, and against the idea of a rigid sectarian division in the Middle East in general, and the Levant in particular.
This speaks to Sadr's independence from Iran. Iranian forces support the Assad regime to the hilt, to the extent that it has effectively become an Iranian proxy, operating alongside numerous Iranian-backed organisations, such as Lebanese Hezbollah and other Shia militias.
Asked whether Sadr represented a significant check on Iranian power within Iraq, Kazimi replied that "his presence, along with Sistani's, already acts as a check on Iran's influence within Iraq". This remains, therefore, "a static situation."
Then I inquired more about Sadr's repositioning.
"I do think that part of this is a sincere reorientation of his thinking," he said.
[Sadr] didn't need the aggravation of mid-2012 when he joined the bid to unseat Maliki, even after reaching a detente with the latter for the 2010 elections. The reasons Sadr laid out for joining the anti-Maliki camp were very progressive if measured against what the larger Shia "establishment" was willing to say about the "oppression" of Sunnis.
"Sadr could have easily competed with Maliki for the Shia chauvinist constituency, given that he had a track record of beating up on Sunnis, or even to use that to cement his alliance with Maliki. Rather, Sadr chose to go the other way."
This points to a sincere reorientation of Sadr's politics.
Other analysts are less optimistic. Some think Sadr is simply jockeying for internal political power, repositioning himself as a reasonable figure and an honest broker in a bid to make himself indispensible.
There is some evidence to suggest this. And it cannot be forgotten that he is a man who led a sectarian insurgency against the new post-Saddam Iraq. His violent past cannot be swiftly forgotten.
At the same time, however, the conflict with IS (Daesh) has changed the state of play. Baghdad came close to capture. Many Iraqis have been killed, either in the face of IS' rapid advance, or in course of the slow, grinding campaign which has retaken so much of the country from the caliphate.
These things tend to focus minds.
So too has the looming prospect of Iranian interference in Iraqi politics. Iran-supporting militias have, by dint of their numbers and the relative weakness of the Iraqi state's armed forces, taken a large role in the anti-IS campaign.
For Iraqi figures such as Sadr, this could have seemed distinctly alarming. He is, as Browne says, a "staunch nationalist". His politics is Iraqi before it is Shia. He has no atavistic loyalty to Iran.
Sadr’s militias represent a nationalist, Iraqi alternative to forces organised from the outside. None of them operate in Syria, unlike many Iranian-backed forces, which happily range across the border between the two countries.
His ambition is to diminish Iranian influence in Iraqi politics, and in doing so he may become an important moderating figure. Sadr could use his high profile and significant support to do something very important.
Even if he's doing much of this for selfish reasons, Sadr’s purported change of heart is still for the good. Iraqi needs moderates, just as its politics needs to moderate. Sadr can counter Iranian influence while also promoting non-sectarian politics.
The Iraqi state has not been truly stable in many years. Paradoxically, the threat of IS has created a new political reality, one in which moderation may win the day, and with it, the sort of stability few thought possible. Sadr could be an essential influence on this new politics. His moderation is an important and positive step. It can only be welcomed.
By James Snell
Copyright @ 2021 The New Arab.