The choices he makes - cooperating with the occupying Americans or opposing them, cooperating with his Shiite rivals or opposing them - will determine not only his own future, but also Iraq's.
And the Sunnis are much closer to Mr. Sadr on some key matters of policy than they are to his Shiite rivals.
With all the ballots from last month's election finally counted, the leader of Iraq's largest Sunni alliance telephoned his Shiite rival on Friday night to wish him well in the weeks ahead.
Though he was abducted in a Sunni neighborhood, there were questions at the time about whether he had been removed by Shiite rivals.
Amal, though larger in number, lacks the money and equipment possessed by its Shiite rivals.
The confrontation there is between Party of God fundamentalists and their Shiite rivals in a pro-Syrian group known as Amal.
Most of the victims were Sunni Arabs; some were Shiite rivals.
The region has been the site of intense battles between the warring Shiite rivals.
It would be remarkable if Mr. Maliki could even reconcile with his Shiite rivals, let alone the Sunni insurgents.
Amal blamed its Shiite rivals in the fundamentalist Party of God and their Iranian backers.