WHAT if George W Bush got up this morning, wandered down to the East Room and told a shocked White House press corps what two-thirds of Americans want to hear . . . US combat forces would begin an immediate withdrawal from Iraq, to be completed within 60 days? "We believe the future of Iraq is for her people to work out amongst themselves, " he'd say. "We've made sure Iraq has no weapons of mass destruction (he he! ), does not have an army that can threaten its neighbours and, while even I got a bit queasy watching on YouTube, we're glad the genocidal tyrant Saddam Hussein is dead. Mission, erm, accomplished."

What happens next?

First, reasonable elements of the European left and humanitarian NGOs would be in an uproar. Facing a humanitarian crisis in Iraq that would see everything from the US invasion till now be remembered as the Golden Age of Iraqi Democracy. Followed by a Kurdish declaration of independence, a Kurdo-Turkish War, and Iranian troops openly engaging Sunni militia inside Iraq. While there may be some who say that a total collapse of central government all over Iraq is preferable to a continued US presence that could be imperial in nature, I suspect most people will be more pragmatic.

I said as much on the Newstalk lunchtime news on Tuesday. The next day, Amnesty International issued a press release demanding that the US Senate appropriate more money for the "refugee crisis" in Iraq. The UK said it would send more money for humanitarian aid, even as it quietly withdraws its own forces before Tony Blair leaves office.

On Thursday, Refugee International released a study claiming that there are now 1.9 million Iraqis "internally displaced" . . . that is, refugees in their own country. The majority of them had moved before the 2003 war but nearly half had fled after the February 2006 bombing of the Golden Mosque in Samarra that marked the beginning of intense direct violence between Sunni and Shi'a.

That's on top of the two million refugees who have already left Iraq, many to Syria or Jordan, depending on their confessional bent.

This isn't news, of course.

Back in December, I wrote about reports that 10,000 Iraqis were fleeing their homes each week and resettling to an area where they felt safer. The Shi'a butcher in a Sunni Baghdad neighbourhood heading to live with Shi'a relatives in the south. The Sunni baker leaving Baghdad for Al-Anbar province.

This isn't "internal displacement". This is slowmotion ethnic cleansing as Iraq coalesces into more homogeneous ethno-religious enclaves of Kurd, Sunni and Shi'a.

The current waffle about a US "surge" has temporarily reduced violence in Baghdad as insurgents simply melt away and decline to give the US army a game until after the US presidential election in 2008. The ordinary Iraqis who risked death to vote by ballot with ink-stained thumbs a couple of years ago . . . when it seemed possible to find a relatively peaceful (relative to what's about to happen) transition to a loosely federated state . . . are now voting with their feet.

Here's a perverse irony: as the withdrawal of US forces from Iraq becomes a more real and imminent probability, those who opposed the 2003 war on humanitarian grounds may find themselves forced to demand that US forces stay in Iraq to prevent a fullscale humanitarian disaster. Who else is capable of doing it? Before I hear the creak of a quarter of a million knees jerking and you say "the UN" it's worth noting last week's UN Baghdad press conference.

"As we see the improved situation on the ground, I am considering to increase the presence of the United Nations, " new UN Secretary General Ban Ki-Moon, standing next to the Iraqi prime minister, told reporters. Minutes later a rocket attack shook the building, splintering the press conference with debris.

Perhaps an Irish peace NGO or even a Dail candidate will propose an Irish-led UN force to protect humanitarian relief in Iraq? No? Didn't think so.

They'd quote Colin Powell, who, according to Bob Woodward's 2004 book Plan of Attack, told Bush in 2002, when war plans were underway, that a US invasion of Iraq would invoke the "Pottery Barn Rule" . . . "You break it, you bought it."

The anti-war movement turned on its head, the US hoist on its own pottery shard.