The international community doesn't do regime change well. Replacing a dictatorship with a democracy is generally best left to the aggrieved citizens themselves, rather than to well-meaning foreigners. Yet the United States did it brilliantly in Germany and Japan after the Second World War.

With Iraq, it was otherwise. It is difficult to conceive of a more disastrously mismanaged international initiative than the U.S. intervention in Iraq. Seizing the opportunity offered by the tragedy of 9/11, George W. Bush and his ideologically committed colleagues went after the dictator they wanted to unseat, rather than pursuing the terrorists who had in fact attacked the United States. The Americans left the Afghan job unfinished, with Osama bin Laden still plying his trade from hideouts somewhere along the Afghan-Pakistani border. They went instead after Saddam Hussein, resting their case for invasion on a tissue of fabrications. Not finding al-Qaeda in Iraq, American policy inadvertently created it there, as well as much of the agony Iraqis have gone through since 2003.

Yet U.S. policy has been present at the creation of some very good developments in Iraq. Some real progress has been made, so much so that it is just possible to imagine that Iraq will stand up as America stands down. How could this be? The establishment of a stable, constitutional regime after the Americans leave would be a colossal achievement. This may well not happen, but one can voice the possibility without being thought a fool. With the United States now commencing its phased withdrawal by pulling its military forces out of the country's towns and cities, the capacity of Iraq's government and institutions will be put to the test, as will its citizens' preparedness for democracy and constitutional government.

For many years, Iraq was an authoritarian dictatorship that offered little scope for normal politics or for the fashioning of the arts of political activity. Iraq possessed little experience with the rules-based systems employed elsewhere to create the public space within which democratic politics can be carried on. Like most authoritarian regimes, Mr. Hussein's was highly centralized, with power concentrated in the president, and policy very much the product of his personal will and preferences. The underlying social and cultural diversity of the society was given little means of expression, and the Sunni population in general and the members of the president's Tikriti tribe in particular were given privileged roles in the governing institutions: the army, the police, the oil and gas industry and the public service.