WASHINGTON - The revelation by Wikileaks of a U.S. military order directing U.S. forces not to investigate cases of torture of detainees by Iraqis has been treated in news reports as yet another case of lack of concern by the U.S. military about detainee abuse.

But the deeper significance of the order, which has been missed by the news media, is that it was part of a larger U.S. strategy of exploiting Shi'a sectarian hatred against Sunnis to help suppress the Sunni insurgency when Sunnis had rejected the U.S. war.

And Gen. David Petraeus was a key figure in developing the strategy of using Shi'a and Kurdish forces to suppress Sunnis in 2004-2005.

The strategy involved the deliberate deployment of Shi'a and Kurdish police commandos in areas of Sunni insurgency in the full knowledge that they were torturing Sunni detainees, as the reports released by Wikileaks show.

That strategy inflamed Sunni fears of Shi'a rule and was a major contributing factor to the rise of al Qaeda's influence in the Sunni areas. The escalating Sunni-Shi'a violence it produced led to the massive sectarian warfare of 2006 in Baghdad in which tens of thousands of civilians - mainly Sunnis - were killed.

The strategy of using primarily Shi'a and Kurdish military and police commando units to suppress Sunni insurgents was adopted after a key turning point in the war in April 2004, when Civil Defense Corps units throughout the Sunni region essentially disappeared overnight during an insurgent offensive.

Two months later, the U.S. military command issued "FRAGO [fragmentary order] 242", which provided that no investigation of detainee abuse by Iraqis was to be conducted unless directed by the headquarters of the command, according to references to the order in the Wikileaks documents.

The order came immediately after Gen. Petraeus took command of the new Multi-National Security Transition Command in Iraq (MNSTC-I). It was a clear signal that the U.S. command expected torture of prisoners to be a central feature of Iraqi military and police operations against Sunni insurgents.

Petraeus knew that it would take more than two years to build a competent Iraqi military officer corps, as he told Bing West, author of the "The Strongest Tribe", in August 2004. Meanwhile, he would have to use Shi'a and Kurdish militias.

In September 2004, Petraeus adopted a plan to establish paramilitary units within the national police.

The initial units were from non-sectarian former Iraqi special forces teams. In October, however, Petraeus embraced the first clearly sectarian Shi'a militia unit - the 2,000- man Shi'a "Wolf Brigade", as a key element of his police commando strategy, giving it two months of training with U.S. forces.

In November 2004, after 80 percent of the Sunni police defected to the insurgents in Mosul, the U.S. command dispatched 2,000 Kurdish peshmurga militiamen to Mosul, and five battalions of predominantly Shi'a troops, with a smattering of Kurds, were to police Ramadi. But a few weeks later, after the completion of its training, the Wolf Brigade was also sent to Mosul.

Hundreds of Shi'a troops from Baghdad and southern areas of the country were also sent into Samara and Fallujah.

It did not take long for the Wolf Brigade to acquire its reputation for torture of Sunni detainees. The Associated Press reported the case of a female detainee in Wolf Brigade custody in Mosul who was whipped with electric cables in order to get her to sign a false confession that she was a high-ranking local leader of the insurgency.

But an official of the U.S. command later told Richard Engel of NBC that the Wolf Brigade had been a very effective unit and had driven the insurgents out of Mosul.

The Wolf Brigade was then sent to Sunni neighborhoods in Baghdad, where the Association of Muslim Scholars publicly accused it of having "arrested imams and the guardians of some mosques, tortured and killed them, and then got rid of their bodies in a garbage dump..."

The Wolf Brigade was also deployed to other Sunni cities, including Ramadi and Samarra, always in close cooperation with U.S. military units.

The war logs released by Wikileaks include a number of reports from Samarra in 2004 and 2005 describing how the U.S. military had handed their captives over to the Wolf Brigade for "further questioning". The implication was that the Shi'a commandos would be able to extract more information from the detainees than would be allowed by U.S. rules.

Gen. Martin Dempsey, who succeeded Petraeus as the commander responsible for training Iraqi security forces in September 2005, hinted strongly in an interview with Elizabeth Vargas of ABC News three months later that the U.S. command accepted the Wolf Brigade's harsh interrogation methods as a necessary feature of using Iraqi counterinsurgency forces.

Dempsey said, "We are fighting through a very harsh environment... these guys are not fighting on the streets of Bayonne, New Jersey." Contrary to the Western notion of "innocent until proven guilty", he said the view in Iraq was "close" to the "opposite".

Vargas reported, "For Dempsey, a big part of building a viable police force is learning to accept, if not embrace, the cultural differences."

A second stage of the strategy of sectarian war against the Sunnis came after the new Shi'a government's takeover of the Interior Ministry in April 2005. The Shi'a minister immediately filled the Iraqi police - especially the commando units - with Shi'a troops from the Badr Corps, the Iranian-trained forces loyal to the Islamic Supreme Council of Iraq.

Within days the Badr Corps, along with the Wolf Brigade, began a campaign of mass arrests, torture and assassination of Sunnis in Baghdad and elsewhere that was widely reported by news agencies.

The U.S. command responded to that development by issuing a new version of the previous order on what to do about Iraqi torture, according to the Wikileaks documents. On Apr. 29, 2005, the U.S. command issued FRAGO 039 requiring reports through operational channels on Iraqi abuse of prisoners using a format attached to the order. But no follow-up investigation was to be made unless directed by higher headquarters.

The former Minister of Interior, Falah al-Naquib, later told Knight-Ridder correspondent Tom Lasseter that he had personally warned Defense Secretary Donald Rumsfeld and other U.S. officials about the sectarian violence by Badr police commandos against Sunnis. "They didn't take us seriously," he lamented.

In fact, the U.S. military and the U.S. Embassy were well aware of the serious risk that the strategy of relying on vengeful Shi'a police commandos to track down Sunnis would exacerbate sectarian tensions between Sunnis and Shi'a. In May 2005, Ann Scott Tyson wrote in the Washington Post that U.S. military analysts did not deny that the U.S. strategy "aggravates the underlying fault lines in Iraqi society, heightening the prospects of civil strife".

In late July 2005, when Petraeus was still heading the command, an unnamed "senior American officer" at MNSTC-I was asked by John F. Burns of the New York Times whether the U.S. might end up arming Iraqis for a civil war. The officer answered, "Maybe."

The U.S.-sponsored Shi'a assault on the Sunnis gave al Qaeda a new opportunity. In mid-2005, Abu Musab al-Zarqawi, leader of al Qaeda in Iraq, announced the creation of a special unit, the Omar Brigade, to combat the Shi'a commando torture and death squads. That led to the massive sectarian bloodletting in Baghdad in 2006, when thousands of civilians were dying every month.