As we know from the Downing Street Memo and from numerous other sources, the US and the UK had made the decision to invade Iraq by no later than the middle of 2002. Blair had gone to Texas to meet Bush in April of 2002 and in the meantime the facts were to be fixed around the policy.
We heard outlandish stories about mushroom clouds, that Saddam was trying to purchase "yellowcake" from Niger, that he was continuing to accumulate weapons of mass destruction and that he had ties to Osama bin Laden and al Qaeda. In time these were all revealed as fabrications and gross exaggerations.
So our intelligence, which was based on National Intelligence Estimate on Iraqi WMDs, was indeed flawed. However two additional NIEs have now been released which show that the Bush Administration should have known very well what difficulties they could expect once Saddam was removed from power.
Paul R. Pillar is on the faculty of George Washington University, a visiting professor for the security studies program there. Mr. Pillar is a Viet Nam War veteran and a 28 year veteran of the CIA, where Wikipedia states that "he was considered the agency's lead analyst in counter-terrorism".
Paul has written an article that appears in Asia Times Online dated 12 June 2007.
Mr. Pillar writes that there were actually 3 National Intelligent Estimates written in the days of the lead up to the war. All three were "classified". Only one, the WMD estimate, is now relatively well known and has been widely ridiculed by those who have read it.
...the US intelligence estimate on Iraqi unconventional-weapons programs ... was excoriated in a 500-page report that the Senate Intelligence Committee issued with much fanfare in July 2004, (and) was further torn apart in another 500-page report by a presidentially appointed commission, and has been the object of scorn and vilification ever since.
... Its public line about Iraqi weapons programs was well-established before it was written ... the president did not even read it - nor did most of the members of congress.
It was Pillar who initiated the other two NIEs, that the public is largely unaware of, and supervised their drafting and coordination in his duties as the intelligence officer for the region concerned with political, economic and social issues.
The other two assessments spoke directly to the instability, conflict, and black hole for blood and treasure that over the past four years we have come to know as Iraq. The assessments described the main contours of the mess that was to be, including Iraq's unpromising and undemocratic political culture, the sharp conflicts and prospect for violence among Iraq's ethnic and sectarian groups, the Marshall Plan scale of effort needed for economic reconstruction, the major refugee problem, the hostility that would be directed at any occupying force that did not provide adequate security and public services, and the exploitation of the conflict by al-Qaeda and other terrorists.
The contents of these NIEs were kept hidden from the public for more than 4 years before redacted versions appeared on the Senate Intelligence Committee website on May 25th just prior to the long holiday weekend. Pillar says they contained very little in the way of sensitive information and should have been much easier to declassify than the Top Secret estimate on weapons.
It now becomes perfectly clear that the Bush Administration knew that they could expect to encounter serious problems in Iraq after overthrowing Saddam. There is no way that they can explain away their failures as being the result of faulty intelligence. The estimates were based on the presumption that the war and occupation would be well executed. Mr. Pillar states that
...the expedition in Iraq was a fool's errand rather than a good idea spoiled by poor execution, implying that the continued search for a winning strategy is likely to be fruitless.
There is additional information in an article at Raw Story with the title Senate report shows intelligence community predicted post-war chaos in Iraq if you are interested in reading more.
The piece by Pillar is also highly recommended.