BAGHDAD (Reuters) - Iraq's anti-U.S. cleric Moqtada al-Sadr is reviving fears of sectarian violence with a warning he will unleash his Shi'ite Mehdi Army militia again if U.S. forces stay in the country beyond a year-end deadline.
But for Mehdi Army veterans like Ahmed, who once battled U.S. troops on Baghdad's streets, the fighting days are over as Sadr's militia enters mainstream politics, struggles with splinter groups, and ex-combatants resist a return to war.
"All I need to do is stay away from any trouble for another three years," said Ahmed, who wants to put his guerrilla days behind him to focus on college exams and becoming a lawyer. He asked that his surname not be used because of his militant past.
At the height of Iraq's 2006-2007 sectarian slaughter, the Mehdi Army was seen by Washington as one of the biggest threats to Iraqi security with its young fighters toting rocket launchers and battling U.S. and Iraqi troops in the streets.
Sadr disarmed his militia after Shi'ite Prime Minister Nuri al-Maliki's troops -- backed by American forces -- defeated them in Baghdad and southern cities in 2008. His movement has since become a potent force in mainstream politics.
Sadr's anti-U.S. rhetoric still inspires followers, and U.S. and Iraqi security officials say Mehdi Army splinter groups still pose a security risk, emerging in the form of Shi'ite militia that Washington says are backed by Iran.
But former fighters and security officials say many Mehdi Army veterans have too much to lose to pick up the gun again.
Iraq's violence has ebbed eight years after the U.S.-led invasion to oust Saddam Hussein, but Sunni insurgents and Shi'ite militias still carry out daily attacks.
The United States still has 47,000 troops in Iraq, but their mandate expires at the end of this year and Iraq's leaders are debating the divisive question of whether to ask some to stay.
Sadr threatened in April to revive his Mehdi Army if the U.S. troops do not all leave Iraq by December 31. He has since brought thousands of Shi'ite supporters onto the streets of Baghdad in a show of strength.
Once a rabble-rousing militant agitator, Sadr is now a powerful member of Maliki's cross-sectarian coalition. His group controls 39 seats in the 325-member parliament, an important bloc in a body divided among Sunni, Shi'ite and Kurdish groups.
The scion of a family of revered Shi'ite clerics, he has taken on a more statesman-like approach even if he has not toned down his anti-U.S. rhetoric. Last year he acted as the kingmaker whose support allowed Maliki to form a fragile, cross-sectarian coalition government.
That mainstream political clout and the benefits his supporters enjoy mean many Mehdi Army veterans may be much less keen to return to arms if Sadr makes that call, Mehdi leaders and Iraqi security officials say.
"Despite his huge number of supporters, if Moqtada decided to fight now, only a few would fight," said Abu Sadiq, a senior Mehdi Army leader in Sadr City, the vast, poor Shi'ite district of east Baghdad named for Moqtada's slain cleric father.
"The only ones who will fight are those who have not become contractors, or parliament members or gained salaries, cars, homes or government posts," he said.
U.S. military commanders and Sunni Arab leaders blamed the Shi'ite Mehdi Army for much of the bloodshed when thousands of Iraqis were killed during sectarian slaughter in 2006-2007.
Sadr's threats have fueled Sunni Arab worries of a return to religious violence.
U.S. and Iraqi officials say a small Mehdi Army faction, the Promised Day Brigade, is still behind attacks on U.S. forces even after Sadr stood down the majority of his fighters.
"He admitted to attacking us and continuing these attacks, and the Promised Day Brigade, that is a Sadrist organization and reports to him, have been making attack claims all along," said U.S. Army Major Gen. Jeffrey Buchanan, a military spokesman.
Sadr spent much of the most violent period in Iran. His return to Iraq this year may have been prompted in part by a need to clean house as rivals within the Sadrist movement were challenging his authority.
Such splits undermine the prospect of a Mehdi Army revival, former fighters say.
"The danger that Moqtada faces is from his leaders who are competing with each other for posts, wealth and positions," Abu Moqtada, a former Mehdi fighter, said.
The biggest splinter group, Asaib al-Haq, is already challenging Sadr, eroding his militia from within by infiltrating the top echelons of his organization, Sadrist sources say.
Asaib, or the Leagues of Righteousness, is headed by Qais al-Khazili, who was a former Sadr spokesman before he broke away. Asaib has its own television station and websites, and Washington says it is funded by Iran.
"We have some leaders inside Sadr's offices and among Mehdi Army troops who follow Sadr publicly but they receive orders from Asaib," said one Sadrist lawmaker who declined to be named because of the sensitivity of the issue.
One senior Iraqi security official, who declined to be named, said Asaib had attracted some skilled Mehdi Army fighters but others were less committed.
"They are not as strong as before, we know most of them are not willing to fight," he said.
But Sadr can still inspire loyal and unquestioning support from young, impoverished men within Sadr City, where some believe he is a holy Imam or saint.
"For me, Moqtada is a saint," said Mehdi fighter, Abu Karar. "I am ready to die for him."
(Writing by Suadad al-Salhy; Editing by Patrick Markey and Peter Graff)