Today Tony Blair is answering questions put to him by the Chilcot committee. The atmosphere is studious and calm, which is right, although many would prefer robust interrogation to a scholarly investigation.
There are a number of background facts and problems which I suspect will not be addressed by the committee today, or maybe ever.
1. Saddam had chemical weapons, and had used them extensively against rebel Kurds. No nuclear materials were found after the invasion, but Saddam's nuclear ambitions had been apparent for years, and had led the Israelis to bomb the Osirak reactor.
The failure to find chemical or nuclear evidence is in itself suspicious. It is hard to believe that intelligence services around the world were so totally wrong in their assessments. Saddam had at least 6 months notice that invasion was likely.
And Saddam had form. His warplanes were hastily flown out to Iran when the first Gulf War opened.
Materials for nuclear and chemical weapons are not bulky, although the industrial plant to produce them may be. Fissile or chemical materials sufficient for several weapons could be transported in an industrial container on one truck. It would be interesting to know if there were unusual movements by road to Syria, or by road or sea to Iran, in the days or weeks before the invasion.
Were there Iraqi nuclear materials in the Syrian facility at Deir Al-Zor, which the Israelis attacked in 2007?
Probably we shall never know.
2. Saddam undertook to destroy his chemical and nuclear weapons programmes at the peace talks at the end of the first Gulf War in 1991. He then failed to comply and co-operate with the United Nations inspectors. Ten years later the western diplomats at the UN were in a quandary: Saddam ignored warnings that 'consequences' would follow if he continued to obstruct and evade.
The UN had to show that it meant what it said, or back off the confrontation, allowing Saddam to boast successful defiance to the Middle East. Politically much strengthened, Saddam's resurgent ambitions would threaten the entire region, indeed much of the world.
Don't threaten unless you are prepared to act: it's a rule fundamental to managing children and dictators.
Don't end a war until the enemy is comprehensively defeated and disarmed: it is an elementary principle of strategy. Ignoring this principle in 1991 was the root of the crisis which developed to a second war 12 years later.
We should never have allowed ourselves to get into that position.
3. The confrontation with Iraq went critical when the military build-up began in the autumn of 2002. Months are necessary to assemble an armoured army for an invasion. As military readiness builds, so the degree of capitulation necessary to justify a retreat increases. Preparations for war have a momentum of their own.
UN authorisation for war, if considered legally essential, should have been settled before the military build-up began in Kuwait. It was a nonsense for our Attorney General to give legal clearance just a few days before war began.
4. The Arabian deserts are an environment hostile to armies, and especially mechanised armies. Once the force is assembled and ready, it must go into action without delay. Heat, drought, dust, disease and boredom will rapidly erode its capabilities. The build-up had taken most of the cooler winter months at the end of 2002.
The invasion began on March 20th., 2003, just about the worst time to begin a military campaign in that desert, with temperatures already stressing men and machines, and the furnace of an Iraqi summer imminent.
And don't forget that at that time the Iraqi army was still among the world's largest and well equipped, on paper at least. There was also the threat of Iraqi resort to chemical or nuclear weapons.
It was go or stand down; final defeat or victory for Saddam. The time for diplomacy had run out.
5. Despite warnings from diplomats and others experienced in the Middle East, and familiar with the Arab mind-set, I suspect Bush and Blair expected allied armies to be greeted by cheering crowds as they entered Baghdad, and full co-operation in establishing a civil government. Instead they had to deal with a frenzy of looting, a collapse of civil order and security, and an orgy of inter-communal violence.
I wrote to my MP before war began, telling him my opinion that the military campaign would quickly succeed, but major problems would begin with victory. I did not foresee just how bad the problems would be, or how long and hard the road to stability, peace and prosperity.
In our western comfort-zone it is hard to believe that Iraqis would loot incubators and surgical equipment from their own hospitals. If we do not know, let alone understand, how can we respond?
6. The final assessment of the Iraq war remains uncertain, but it will not be good. Saddam lost the war, but the west lost the peace. Now we stand weakened before a greater crisis developing with Iran.