On 15 September US commanding general David Petraeus reports progress about the "surge" . . . the last effort by the US military to establish security in Iraq.

As support among Americans for the war continues to decline, all sides are gearing up for the debate that will follow about what to do next.

The case for remaining in Iraq . . .pitched to an American audience . . . is neatly summed up in a TV ad made by a group called Freedom's Watch. It features Iraq veteran sergeant John Kriesel: "If we pull out now, everything I have given in sacrifice will mean nothing. They attacked us, and they will again. They won't stop in Iraq. We are winning on the ground and making real progress. It's no time to quit."

A recent New York Times article by two analysts from the left-of-centre think-tank the Brookings Institution, headlined 'A War We Just Might Win', seemed to give the argument . . . that a US victory in Iraq is still possible . . .some intellectual respectability.

In the video, Kriesel emerges from a doorway with two artificial legs just as he says "sacrifice." The ad sets up a 'stab in the back' narrative for after the US leaves, arguing that leaving now will repeat the "real" tragedy of Vietnam for some on the right: the US could have "won" had it not been forced by anti-war protesters to betray south Vietnam.

Last week John Warner, the silver-haired Republican who has represented Virginia for 30 years in the Senate and supported the invasion of Iraq, argued that the US should begin a withdrawal.

Warner's comments offer cover to other former supporters of the war who want out. But the reasons offered by proponents for withdrawal are generally couched in a shameful 'blame the victim' argument: the US should pull troops out of Iraq to force the squabbling, incompetent Iraqis to get along and start governing themselves.

Neither the 'blame the victim' nor the 'stab in the back' narrative challenges the underlying premise that the US is leaving Iraq. It's simply a fight about who is to blame.

And there are signs the question may not wait until after the next US election for an answer. Since the invasion, the US military effort focused on getting elections underway and protecting the status quo. Now, the US has realised the quasi-democratic status quo can't go on. The new, new, new idea for what next in Iraq, it turns out, is dictatorship.

Earlier this year a New York academic conference published a report of a one-day seminar identifying three plausible scenarios for Iraq in 2010. The best-case scenario, from a US point of view? The emergence of a 'National Unity Dictatorship'.

Following a significant US withdrawal, someone from within the Iraqi Army, perhaps commander lieutenant general Aboud Qanbar, steps up and seizes power in a coup, tapping "dormant strains of Iraqi nationalism" to defeat al-Qaida in Iraq, Sunni militants, Iranian agents, Shia militias . . . and copperfastens power by getting the US to finally pack up.

It's the 'best case' because it's the only one that sees Iraq not partitioned into Kurdistan, the Islamic Republic of Basra and the Sheikhdom of Anbar. Never mind that a regionally negotiated partition seems the least appalling and least bloody option.

That paper has made the rounds. There are signs it's now US policy to allow the 'best case' scenario to unfold.

Last week, Bush distanced himself from the elected prime minister, Nouri al Maliki. And in a trial balloon, a US commander, brigadier general John Bednarek, told CNN: "Democratic institutions are not necessarily the way ahead in the long-term future [for Iraq]."

So after four years, thousands dead and billions spent, it could turn out the US went to war to make Iraq safe for a kinder, gentler Saddam Hussein. Kriesel's sacrifice wasn't meaningless.

It was far, far worse than meaningless.

I hate Iraq. I wish we had never gone to the place.