Mr Bush spoke of the massacres under Cambodia's Khmer Rouge,"The defence strategy that refused to hand the South Koreans over to a totalitarian neighbour helped raise up an Asian Tiger that is a model for developing countries across the world, including the Middle East."

Mr Bush compared current calls for withdrawal from Iraq with what happened at the end of the Vietnam War in 1975.

"Many argued that if we pulled out, there would be no consequences for the Vietnamese people," Mr Bush said. "The world would learn just how costly these misimpressions would be.

"Three decades later, there is a legitimate debate about how we got into the Vietnam War and how we left.

"Whatever your position in that debate, one unmistakable legacy of Vietnam is that the price of America's withdrawal was paid by millions of innocent citizens," Mr Bush said, mentioning reprisals against US allies in Vietnam, the displacement of Vietnamese refugees and the massacres in Cambodia under Pol Pot's Khmer Rouge.

There was another price to our withdrawal from Vietnam, and we can hear it in the words of the enemy we face in today's struggle -- al-Qaeda. In an interview with a Pakistani paper after the 9/11 attacks, Bin Laden declared that 'the American people had risen against their government's war in Vietnam. They must do the same today.' . . . . Here at home, some can argue our withdrawal from Vietnam carried no price to American credibility -- but the terrorists see things differently."

I think that Levin is absolutely right that the Iraqi government is not working. But this does not begin to imply that the Iraqis would be well advised to oust Maliki, let alone that we should be advising them to oust him. That would follow if Maliki were the reason the Iraqi government was dysfunctional (or: a significant part of the reason.) Suppose, for instance, that most members of the Iraqi parliament were ready to compromise with one another. Deals were ready to be struck, compromises were in hand, but alas! Nouri al-Maliki stood in their way, using his power as Prime Minister to block them all. In that case, it might be a good thing if he were replaced.

On the other hand, suppose the reason the Iraqi government is not functioning is that its various members are not prepared to come to terms with one another and try to resolve the outstanding issues that divide them. Maybe they believe that a civil war is imminent, and that they should concentrate on being in the best position to win it once it starts rather than trying to prevent it; or maybe they are just incapable of putting aside their sectarian and ethnic differences and working for the good of the country. In that case, there would be no reason at all to suppose that replacing Maliki would solve anything. He might or might not be the best person for the job, but that wouldn't really matter: if no one could make the Iraqi government functional, then the particular characteristics of Nouri al-Maliki are beside the point.

Unfortunately, I don't see a single indication that Maliki himself is the problem...the Prime Minister could be replaced twenty times over and it wouldn't make the slightest difference. What it would do is cause months of delay while the new Prime Minister tried to put together his government.

Democratic leaders in Congress had planned to use August recess to raise the heat on Republicans to break with President Bush on the Iraq war. Instead, Democrats have been forced to recalibrate their own message in the face of recent positive signs on the security front, increasingly focusing their criticisms on what those military gains have not achieved: reconciliation among Iraq's diverse political factions.

"America must remember one of the lessons of the Vietnam War. Then, as now, we fought a war with the wrong strategy for several years. And then, as now, we corrected course and began to show real progress. Many historians today believe that by about 1972 we and our South Vietnamese partners had succeeded in defeating the Vietcong insurgency and in setting South Vietnam on a path to political self-sufficiency. But America then withdrew its support, allowing the communist North to conquer the South...The consequences of abandoning Iraq would be worse."