The liberation of Iraq from the murderous dictatorship of Saddam Hussein remains a good deed in a sorry world. As the silent witness of the dead in Srebrenica, Rwanda, Congo, Darfur and Zimbabwe attest there are a lot worse fates than to be saved by western intervention. But while it is one thing to defend the decision to topple Saddam, it is quite another to argue that every course that followed has been right. News reports show the daily horrors of life in the Sunni triangle. Revelations — such as our reporting of the Downing Street memo — have made it clear that the White House and Downing Street were less than frank with the people in the countdown to war. In this climate it is counter- productive to respond with Panglossian assurances that everything in Iraq is now for the best in the best of all possible worlds. The cameras and the documents may not show the whole picture but they do not lie.

This refusal to acknowledge reality has been damaging. If advocates of the war are not telling the full story about the post-war security mess, their words with regard to the bigger picture of the insurgency will be deemed to be equally untrustworthy. There were not enough coalition troops in Iraq in the immediate aftermath of the invasion. Security broke down and the insurgents were given a breathing space in which to establish themselves. But this truth is simply denied, persuading nobody. It adds conviction to the idea that the whole project is somehow illegitimate.

Two weeks ago Vice-President Dick Cheney said that the insurgency was in its “last throes”. He offered no evidence for this assertion. Instead, a recent CIA report on the insurgency argued that the jihadists had learnt how to improve their techniques and the constellation of battle hardened terrorists developing in Iraq risked becoming a training ground for terror across the world.

In one sense it is understandable that neither President George W Bush nor Tony Blair wants to admit the grave worries about what may develop in Iraq and the huge difficulties in turning a country from three decades of Ba’athist dictatorship into a thriving democracy. Emphasising the positive is important. There are indeed strong positive signs. The economy is recovering. Much of Iraq is relatively untouched by the insurgency. The elections were an inspiring sign of the Iraqis’ desire for democracy, just as the development of an internal Iraqi militia shows that there is an appetite among the Iraqis themselves to defeat the terrorists. There are also splits emerging between the Sunni nationalists and foreign jihadists.

But to ignore the negatives is to ignore reality. Unless the failures are recognised they cannot be rectified and that means a further slide from a peaceable, democratic Iraq. Last week Joe Biden, the Democrat senator, returning from Iraq, criticised the “long litany of rosy assessments, misleading statements, premature declarations of victory that we’ve heard from the administration on Iraq”. His point was that the consequences of failure will be so dangerous that it is in nobody’s interest to ignore the problems: “The future, if it results in failure, will be a disaster.”

With every passing day of bland reassurance, the credibility of Mr Bush — whose approval ratings in the US are in freefall — and, of course, of Mr Blair takes a further knock. The divisions over Iraq policy need to be healed. That means concentrating on the future and the building of genuine Iraqi self-government. But it also requires honesty about what is happening and what needs to be done. Mr Bush should take a leaf out of his predecessor Franklin D Roosevelt’s book. On February 23, 1942, FDR told his countrymen: “Your government has unmistakable confidence in your ability to hear the worst, without flinching or losing heart. You must, in turn, have complete confidence that your government is keeping nothing from you except information that will help the enemy in his attempt to destroy us.”