I've just been sent an article by Richard Overy, from an Evening Standard journalist. He emphasises the point that while the "coalition" forces stay in Iraq, they give the guerrilla insurgency a target and a motive, and perhaps that pulling the troops out would deflate the insurgency and help speed Iraq back towards peace. He also describes very well how the aim and method of "exporting democracy" is fundamentally misguided, and that the most hopeful examples in recent history are of change coming from within (e.g. South Africa - although there were obvious external pressures acting as well).
It's an interesting argument that the troops should pull out in order to remove the purpose from the insurgents. But the article leaves out the fact that the US/Britain/others need to maintain a commitment to Iraq in terms of making reparations for the destruction of the country's infrastructure. Most Iraqis don't have access to the acceptable standard of water, electricity, or medical facilities that they did before the war. The invading nations have an absolute obigation to ensure that they do, and they need to do it using their own money and resources (not with Iraqi oil money, as the provisional authority has been doing).
I fear that to pull out altogether, and to attempt reparations purely at a distance (e.g. just by pumping money in), would have two problems. Firstly, it's vulnerable to corruption taking the money away from its intended targets. Secondly, it makes it easy for reparations to slide out of the Western public consciousness, and for our governments to cut back their support.
So we need to push forward on projects to (re)build medical centres and schools. Whether Iraq eventually becomes a real democracy or not, that's the only way to win hearts and minds and ensure that this terrible misadventure doesn't create many more enemies than we already had.