The report of the Iraq Survey Group should put an end to a saga which will go down as one of the great failures in the history of intelligence.
By Paul Reynolds
BBC News Online world affairs correspondent
Saddam was a potential not an immediate threat, says the ISG report
The group concluded it was unlikely that Saddam Hussein had weapons of mass destruction.
It also concluded that he probably meant to make chemical weapons again one day, if sanctions had been lifted.
"The emphasis is on capability and intention not on immediate threat," said one British official familiar with the report.
While the technical assessment is over, barring some unexpected discovery, the political argument is not.
Opponents of the war will quite simply feel vindicated. For them it was an open and shut case which has now been finally shut. Iraq had no weapons and the inspections would have revealed this if they had been allowed to continue.
The assessment that Saddam Hussein was a potential threat provides an escape clause for proponents of the war, even though it was not the basis on which the decision to attack was taken. The basis for war was that he was an imminent, not a potential threat.
Already the Foreign Office in London is saying that Saddam Hussein was "in striking distance of ending sanctions" (though presumably the US and UK could have vetoed any move by the Security Council to do this), that he had a secret oil distribution programme amassing him some $2bn, had never abandoned his intention of acquiring chemical weapons and would resume his WMD activities once sanctions had gone, something fully understood by his lieutenants.
"On the basis of the report, we should accept that Saddam had the capacity to develop WMD," British officials said.
Why did intelligence fail?
As well as being a huge failure of intelligence, it is also a huge mystery. How could intelligence services have been so wide of the mark? Rarely have so many been so wrong about so much.
The blandly named Iraq Survey Group, made up of weapons experts led by the Americans and with input from the British and Australians, does go some way to providing part of the answer.
Iraq once had Scuds and planned more rockets, says report
The group tried to penetrate the psychology of the Iraqi regime and had access to interrogations with Saddam Hussein and with his associates like his former Foreign Minister Tariq Aziz.
It came up with the theory that Saddam Hussein's dark mind was convinced that his power lay in his special weapons and that, even though he had to give them up after the first Gulf War in 1991, he was determined to preserve an ability to manufacture them.
At the same time, he wanted to maintain the myth of invincibility which the weapons had brought him. He always believed that it was the threat of the weapons which stopped the Americans from going to Baghdad in 1991. So he obscured what he had and did not have.
His priority was not to rebuild his weapons. That would have ensured the continuation of sanctions. It was to get rid of sanctions and to subvert them in the meantime.
He was prepared to wait his time until the outside world lost interest and left him alone.
This, and the system of fear and rewards he ran which was unfamiliar to the West, made his regime hard to read. He did not, as South Africa and Ukraine did, throw open his doors willingly and allow easy inspection.
Indeed, the inspectors left at the end of 1998. Their chief, Richard Butler, at first said that they had been hampered in their work then that they had been ordered out by the UN for their safety in advance of the bombing of Iraq known as Operation Desert Fox.
In any event, suspicion remained and suspicion led to errors of judgment in which Saddam Hussein was not given the benefit of any doubt, even when the inspectors returned and found nothing.
It proved a disastrous strategy for Saddam Hussein because the uncertainty about his weapons could be exploited by an administration in Washington quite prepared to go to war.
It turns out that the only area in which a reasonably accurate assessment was made was in rocketry. Here, ironically, the threat was probably underplayed. Iraq had plans, according to the Survey Group, for a rocket with a range of 1,000km (620 miles), far in excess of the 150km (90 miles) he was permitted by the United Nations sanctions rules.
Then and now
The road to this conclusion has been a long one.
It is a long way from the confidence of the British government document in 2002 called Iraq's Weapons of Mass Destruction.
In that dossier, UK Prime Minister Tony Blair claimed: "What I believe the assessed intelligence has established beyond doubt is that Saddam has continued to produce chemical and biological weapons, that he continues in his efforts to develop nuclear weapons, and that he has been able to extend the range of his ballistic missile programme."
It is a long way too from the CIA document, also from the autumn of 2002, whose first line read: "Iraq has continued its weapons of mass destruction (WMD) programs in defiance of UN resolutions and restrictions."