The NYT's account of systemic use of torture largely by Shiites on Sunnis, revealed in the Wikileaks doc-dump, is here. It's horrifying - along the lines of Abu Ghraib and Bagram, but also, in many cases, even worse and cruder. It occurred during US occupation of the country; although most of the torture was perpetrated by Iraqi security forces, and although on occasion American forces prevented torture, some occurred under American control, and there was inevitable enmeshment as they fought alongside:

The documents show that Americans did sometimes use the threat of abuse by Iraqi authorities to get information out of prisoners. One report said an American threatened to send a detainee to the notorious Wolf Brigade, a particularly violent Iraqi police unit, if he did not supply information.

Some of the worst examples of Iraqi abuse came later in the war. In August 2009, an Iraqi police commando unit reported that a detainee committed suicide in its custody, but an autopsy conducted in the presence of an American “found bruises and burns on the detainee’s body as well as visible injuries to the head, arm, torso, legs, and neck.” The report stated that the police “have reportedly begun an investigation.”

Then in December, 12 Iraqi soldiers, including an intelligence officer, were caught on video in Tal Afar shooting to death a prisoner whose hands were tied.

Ambers has a summary here. The Guardian:

In two Iraqi cases postmortems revealed evidence of death by torture. On 27 August 2009 a US medical officer found "bruises and burns as well as visible injuries to the head, arm, torso, legs and neck" on the body of one man claimed by police to have killed himself. On 3 December 2008 another detainee, said by police to have died of "bad kidneys", was found to have "evidence of some type of unknown surgical procedure on [his] abdomen".

The forces that conducted these horrific acts are the forces we are handing the country over to. History will harshly judge this war, and those of us who supported it, its long-term strategic effect, and so forth. In particular, it appears, that one of the main actors was Iran, and Iran has emerged as the core winner. But the hell unleashed by the incompetent occupation led to over 100,000 often gruesome civilian deaths in what was a nation-wide bloodbath of almost frenzied proportions.

I think it can be said, now more forcefully than ever, that whatever moral legitimacy this war once had is now gone forever.

It was worse than a mistake. It was, in many ways, a crime.