Five years ago I was worried that the war in Iraq would not occur. Let me be more specific. Five years ago I was concerned that the international community would fail to hold Saddam Hussain to UN resolutions about Weapons of Mass Destruction. Such a weakening of the UN, in the wake of the attacks on the 11th of September 2001, was clearly an unacceptable risk. In addition, I hoped that the removal of Saddam by an outside force might provide a mechanism for liberating the Iraqi people, without the disastrous consequences of the civil war that would undoubtedly have taken place if he had fallen by some as yet unseen mechanism. For me, the humanitarian aspect was always of equal importance.

We know now that the decision to enforce resolution 1441 was correct. Saddam Hussain was not in compliance. Thankfully, chemical weapons were not used on our troops, and it appears that Saddam Hussain fooled all the intelligence agencies of the world, as well as many of his own military staff. Less helpfully, this has seen the arguments about WMD made in good faith represented as deliberate lies in order to start a war for ignoble purposes (insert your own purpose here).

Sadly, the consequences of the war have been disastrous in terms of the level of human suffering, whatever the estimate you choose for the level of civilian deaths. There were clear failures of post-war management and failures of imagination. Both Bremner and Rumsfeld, the latter who was kept in post long after the failure of his policies was apparent, carry a large responsibility for this. The disbanding of the Iraqi army was a tactical mistake. Far too few troops were deployed. Naive staff were put in charge of important post-war reconstruction projects. Failures of imagination include: not judging correctly how Iran’s interests would be played out in the region and not clearly appreciating how Al Qaeda had already mobilised jihadist forces by carrying out 911 successfully. A Western force in a recently destabilised Arab nation with porous borders, viewed down the retrospect-o-scope, was always going to be a magnet. These twin perils have been largely behind the failure of Iraq up to the end of 2006.

Of course, the decision to invade Iraq was made and cannot be retreated from, even if the Liberal Democrats appear to simplistically believe they can (Witness Charles Kennedy on Newsnight tonight). One cannot easily calculate the losses that would have occurred if the invasion had not taken place, but it is clear that supporters of the war were wrong in their assessment of the capacity of Iraq to recover after Saddam been removed, and were overly optimistic in the light of other liberal humanitarian interventions that had recently occurred. However, those still living in February 2003 should break out of their chains, and focus on February 2008 and what the right policy should be now.

Gerald Baker in the Times correctly notes that the failure in Iraq is due more to a lack of neoconservative influence at the Whitehouse, rather than a surfeit.

In fact, you could easily argue that it was an insufficiency of idealistic neoconservative zeal, not an excess of it, that so undermined US military efforts in Iraq.

Mr Rumsfeld especially, as he is expected to argue in his forthcoming memoirs, never much believed in the idea that the US should try for a transformation of the political culture of Iraq. That was presumably why he resisted the calls of some neocons for a much greater commitment of US military resources to the war. His favoured approach seems to have been a quick victory over Saddam, his replacement by a US-friendly government and a quick exit by US forces, not the long occupation that real political transformation evidently requires.

What is more, it is probably fair to say that it was only when Mr Bush dismissed Mr Rumsfeld and started to listen more closely to what neoconservatives such as the AEI scholar Fred Kagan were saying that US fortunes in Iraq began to turn around.

Mr Kagan was one of the intellectual authors of the “surge”, the steep acceleration of US military efforts that was hatched last year and which seems to have produced the clearest signs of success in stabilising Iraq since the US invaded five years ago.

Five years on we have the responsibility to finish what we have started. Rumsfeld can be wrong on more than one issue. Let us hope he is wrong about the chances of democracy taking root in Iraq.